Measuring Chemicals Directly on Human Skin in a Non-Invasive Fashion

Interview conducted by Stuart MilneMay 16 2016

Amay Bandodkar, the doctoral candidate in the Department of NanoEngineering at the University of California, San Diego, talks to AZoM about his research into wearable devices that measure chemicals directly on human skin in a non-invasive fashion.

Can you provide our readers with an overview of your research?

My research is focused on wearable devices that measure chemicals directly onto the human skin in a non-invasive fashion. Most of the workaround wearable sensors have been focused on measuring physical parameters such as heart rate, temperature, body motions, etc. However, if you want to have a complete overview of a person's well-being, it is really important to not only measure the physical parameters such as temperature or ECG but to also measure chemicals. It’s only through such an approach that one can acquire a holistic view of the person's well-being.

You recently won the young chemist award from Metrohm USA for your research into wearable sensors. Why are the wearable sensors you are developing differently to currently available solutions?

When people ask me, “what is the current status of wearable sensors?” I use two words - Johnny Bravo. The guy with an impressive upper body and weak lower body. Chemical sensors are essentially the lower body of Johnny Bravo. The market is not focusing on what it is really important to have, a sensor that can do both chemical and physical sensing. My research is focused on developing wearable sensors that will complement the physical sensors, and give a more holistic view.

Are there any specific chemicals you’re looking for?

It depends on the application; for example, blood glucose is one of the most critical chemicals to monitor diabetes. Approximately 400 million people are affected by diabetes and this number is only expected to grow. Diabetes is a big problem and right now, the most common way of measuring blood glucose level is to prick your finger, take the blood samples, and then do the test, which is not very consumer-friendly.

We are developing wearable glucose sensors that can test glucose levels without the need for a finger prick. We are also looking at forensic applications. Our wearable forensic sensors can detect gunshot residues, explosives, cocaine or drugs, etc. At present, the only way to do such tests is to physically collect the samples and to send them to a centralized facility for analyzing. Our wearable sensors allow users to detect the samples on the same spot.

We are also looking at environmental applications for detecting toxic gases and other pollutants. We are working on a broad range of applications.

Can physiologically relevant chemicals in the human body be monitored by other methods, and what benefits do the wearable sensors you have developed offer in comparison?

The best example would be the blood glucose meter, which is a handheld device where you have to prick the finger, take the blood sample, and do the detection. It involves finger pricking, which is not very comfortable.

Our wearable non-invasive sensors can do this, but without the need for blood sampling. We have also correlated our sensors with blood glucose meters that are already in the market. We’ve seen a really good correlation between the blood glucose meters and the non-invasive blood glucose meters.

Another example would be monitoring other biochemicals in the blood. Measuring these bio-chemicals requires big machines to do the testing.

Compare that with a small wearable patch that you can easily put on your skin. The user can do their physical activity and whatever else they want, and the sensor continuously measures the information and sends it from the sensor to your cell phone or your laptop. From there it can be easily distributed around the world, so it's more like internet of things device. Connecting several sensors together and getting more information about the person, not just one point data.

What are the next steps in the development process?

We are looking into commercial partners who are interested in commercializing our technology, but from an R&D point of view, we certainly have a long way to go. We want to analyze these devices much more. We are in the process of conducting larger-scale population studies and are collaborating with different groups in this regard.

We want to study how the person's skin, age, sex, ethnicity etc. affects the sensor response. The development requires collaboration with many different groups. At the same time, we want to make these devices more “skin-like” so that they can stretch and also self-heal (upon damage) just like the human skin.  

These devices need to be integrated with wearable wireless electronics that can acquire, analyze, and transmit the data to the wearer. Therefore, we collaborate with the groups that have expertise in developing low-power wireless electronics.

We also are looking forward to collaborating with computer scientists, who do data analytics. These sensors are going to collect a lot of information, but it is going to be overwhelming and too daunting for the user to understand. So it is really important to send the most relevant information to the user and not all of it. Hence Bid Data analytics is bound to play a crucial role in the field of wearable sensors. We are also working with visual artists. It is important that these sensors are attractive. The visual artist brings arts into science. So it is not just STEM, but STEAM research.

The success of the field of wearable sensors truly requires a multi-disciplinary research approach. It’s because of this reason that UC San Diego has established the Center for Wearable Sensors, which brings various research groups that have expertise with diverse fields on a common platform to collaborate and solve the most challenging issues faced by the wearable sensors.

Printable inks are becoming more widely used for a variety of printable electronic applications. Could you tell us about the inks you're fabricating?

Indeed the field of printed electronics is growing by leaps and bounds. My research is primarily focused on developing inks that allow printed devices to have "skin-like" features, including softness, stretchability, and self-healing. We develop these inks by combining specific binders, conductive fillers, and other additives. The nature of these ink components depends on the final properties desired by the inks.

Were there any major obstacles you have overcome whilst conducting your research into this area?

We encounter challenges at almost every step of our research. One of the most pressing challenges that we face is finding optimal strategies to immobilize delicate biomolecules on our wearable printed devices so that they perform as expected even under harsh conditions common to wearable devices, for example; mechanical stress due to body motion, varying ambient conditions, long-term stability, etc.

Another important challenge is the issue of the seamless integration of our devices with other wearable electronics. Fabricating "skin-like" wearable devices is also a daunting challenge. Such "skin-like" electronics are critical so that the wearer experiences no skin irritation while wearing these devices for a long duration.

About Amay Bandodkar​

Amay J. Bandodkar is a doctoral candidate in the Department of NanoEngineering at the University of California, San Diego.

His research interests lie in the development of wearable electrochemical devices for healthcare, environmental, and security applications.

He is the recipient of the 2016 Metrohm Young Chemist Award, 2016 MRS Graduate Student Award (Silver), 2016 Siebel Scholars Award, 2015 Interdisciplinary Research Award, and 2011 Undergraduate Research Publication Award in recognition of his engineering and leadership qualities.