How can wearable sensors help monitor health and tailor drug treatments?
Currently, most healthcare is based on reactive medicine; when we get sick, we go to a doctor who prescribes us some medicine or a treatment that will hopefully make us feel better. But what if we could stop ourselves from getting sick in the first place? Dr Netz Arroyo at the Johns Hopkins School of Medicine and the University of North Carolina Chapel Hill, USA, is developing wearable sensing devices that can monitor health in real time. This will allow doctors to tailor treatments to individuals and potentially prevent illness from taking hold in the first place.
Talk like a… biomedical engineer
Aptamer — a short piece of DNA or RNA that can recognise and bind to specific molecules, such as proteins or drugs
Biofluid — bodily fluids such as blood, saliva, sweat and urine
Continuous molecular monitor (CMM) — a sensing device that measures health information from the body in real time
Electrochemical aptamer-based (E-AB) sensor — a type of CMM that can detect and measure specific target molecules that are medically important
Preventative medicine — a proactive approach to healthcare that aims to prevent health issues before they arise through regular testing and monitoring, and by encouraging healthy lifestyles
Reactive medicine — responding to and treating health issues that have already arisen
Many of us are familiar with wearable technologies such as smart watches and Fitbits, which can track our fitness by giving real-time measurements such as heart rate, step count or blood pressure. However, Dr Netz Arroyo at the Johns Hopkins School of Medicine believes that these devices have not yet reached their full potential. “Imagine if we could track your stress hormone levels, inflammation status or nutritional health via measurements of molecules directly in your body,” he says.
Netz hopes to make this a reality by designing a new type of continuous molecular monitor (CMM). “CMMs could be used to monitor your health status on the go, to shift away from reactive medicine, where you get sick and we give you medication to cure you, to preventative medicine, where we monitor your health molecules to make sure you don’t get sick in the first place,” explains Netz. “Ideally you do not want to have to wait until you get sick to see a doctor, because by this time your condition may be irreversibly bad.” For example, some cancers can spread throughout the body before a patient feels any symptoms; by which point the cancer may be untreatable. A CMM may be able to detect the cancer before it spreads, enabling doctors to treat the patient in a timely manner, potentially saving their life.
Personalised healthcare
Think about the people around you: your classmates, teachers, family and friends. Each one of them is unique, with their own body, personality and lifestyle. We differ from each other in countless ways, including age, gender, ethnicity, size and shape, exercise and activity levels, and the types and amounts of food we eat. However, for many illnesses, we are all treated in the same way. For example, although drugs and medicines are often vital for treating an illness, the amount of a drug given to each patient is often one-size-fits-all.
On the other hand, drug doses are sometimes decided experimentally, meaning that doctors have to prescribe different doses to a patient using trial-and-error until they find an amount that works. As a result of our uniqueness, a drug dose that works for one person may not work for someone else. “CMMs could be used to improve medication dosing by personalising your dose to your own body or metabolism, minimising side effects while enhancing therapeutic benefit,” says Netz.
Continuous molecular monitors
There is currently only one type CMM that is commercially available: the continuous glucose sensor. This sensor has changed the lives of many diabetics, allowing them to monitor how effective their treatment is and make necessary adjustments by tracking their glucose levels at any time of the day or night. However, the CMM technology used in this sensor does not work for other health conditions due to the differences in the types of molecules that may need to be tracked.
“The continuous glucose sensor uses an enzyme called glucose oxidase to turn glucose into electrons via a chemical reaction,” explains Netz. “Unfortunately, there are not many enzymes that can be used in the same way for other molecules that we may want to monitor for medical applications.” Netz hopes that his new type of CMM will bypass this problem.
“Electrochemical aptamer-based (E-AB) sensors are molecular monitors that can measure a great variety of molecules in biofluids within the body, in real time,” explains Netz. E-AB sensors consist of an electrical conductor, such as a wire, which is coated with a modified piece of DNA or RNA called an aptamer, chosen due to its ability to bind to a specific target, such as a drug, a virus or a cancerous cell. The aptamers are modified with a molecule called a redox reporter, which allows a small electrical current to be generated when the aptamer binds to its target. “The amount of current that E-AB sensors generate is directly proportional to the concentration of the molecule we want to detect in the body,” explains Netz.
A work in progress
“Current E-AB sensors have a continuous sensing lifespan of only about 12 hours,” says Netz. This is because the sensors can be damaged by the voltages running through them and by certain components of biofluids. Netz is developing new ways of manufacturing E-AB sensors with the goal of creating sensors that can work continuously for a fortnight.
Netz has also found that some target molecules, such as some proteins which are associated with inflammation, are too large to monitor with the current technology. He says, “Developing E-AB sensors for proteins is an active field of research but, unfortunately, a simple, universal solution to continuously detecting large proteins has not yet been found.”
What successes has Netz had so far?
“So far, we have successfully demonstrated that the E-AB technology can monitor molecules in the body of live rodents for hours,” says Netz. He has also demonstrated that the sensors can be used to help diagnose some illnesses with as much success as some commercially available tests. “Finally, we have licensed the technology so that startups around the world can help us advance E-AB sensors for commercial and medical applications,” continues Netz. “By allowing us to monitor health molecules in the body, E-AB sensors have the potential to not only better treat disease, but also to prevent it altogether.”
Reference
https://doi.org/10.33424/FUTURUM592
Netz Arroyo, Ph. D.
Associate Professor, Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, USA
Fields of research: Biomedical engineering, electrochemistry, in-vivo biosensing, analytical chemistry, pharmacology, DNA nanotechnology
Research project: Developing wearable continuous molecular monitors that can help us track our health and manage diseases
Funders: US National Institutes of Health (NIH), Air Force Office of Scientific Research (AFOSR), Helmsley Trust
About biomedical engineering
Biomedical engineering focuses on finding solutions to medical problems using principles from engineering. Biomedical engineers are interested in the underlying causes of disease, and in creating and improving diagnostic and therapeutic tools.
“The potential to solve problems that may ultimately improve our quality of life and improve patient care is a great motivator,” says Netz. “Biomedical research is already moving towards preventative healthcare, but more work has to be done.”
A multidisciplinary approach to biomedical engineering is incredibly important. “I would argue that in today’s world, most simple problems have been solved,” says Netz. “The next step is to pursue much more complex problems in biology, which needs the integration of multiple disciplines. For example, to make a sensor, we need expertise in chemistry, engineering and pharmacology.” Netz advises that students learn as much as they can in whichever subjects they are studying. “Never say, ‘This knowledge will never be useful to me’. The reality is that you never know what knowledge will be useful to you, and when,” he says.
Just as there is diversity within the general population, and therefore the patient population, Netz believes it is important for there to be diversity and inclusivity within the research community. He says, “Diversity and inclusivity are pillars for healthy career growth and the scientific community.”
For Netz, the complex nature of biology is one of the biggest challenges in biomedical research. “Many, many ideas fail, and this can be emotionally devastating,” he says. “The way we overcome the frustration of failing is by taking good rest, exercising and doing activities outside of work that nourish the soul. Then we go back to the lab to try again.”
The motivation to succeed drives Netz and his colleagues forwards. Netz says, “Imagine that a discovery made by you could save someone else’s life, or drastically improve comfort and public health at a national scale.”
Pathway from school to biomedical engineering
Study biology, mathematics and chemistry at school to develop a strong foundation. These are likely to be required subjects for university or apprenticeships.
Subjects such as engineering and pharmacology may also be helpful, and a good understanding of statistics and coding will be useful when analysing results.
Netz says, “Reach out to a scientist, such as a professor at a university, and ask if you could do some work in their lab. Being exposed to the challenges of doing hands-on research can be highly informative and useful for making decisions about your career.”
Netz also suggests making the most of free online platforms, such as YouTube or Coursera, to learn new skills and explore your interests.
Explore careers in biomedical engineering
The Institute of Biomedical Science website is packed with information about the latest research, qualifications and career paths, mentoring schemes, and more. You could even consider becoming a student member and attending some of their events.
The UK’s National Health Service (NHS) has a helpful webpage about careers in Biomedical Science.
In addition to roles in healthcare settings and academic institutions, studying biomedical engineering can lead to careers in areas as diverse as journalism, the armed forces, the brewing industry or veterinary science.
Meet Netz
As a teenager, I was interested in building tools and helping people. These interests eventually led me to medicine and then to chemistry.
The thing I love most about my job is mentoring students. You can have a really strong, positive impact on the life of your students and see them grow and succeed, which is emotionally rewarding.
I am proud of being born in Puebla, Mexico, and having worked hard to be in the position I enjoy today at Johns Hopkins University. For a guy like me to have made it to the major leagues of academic research at an internationally recognised institution is an incredible honour.
One of my career highlights is that I was the first to demonstrate that we could use electrochemical aptamer-based sensors to monitor molecules in the body. Since my seminal paper, which was published in the Proceedings of the National Academy of Sciences of the United States of America, I have made many contributions to the area of biosensor development.
I am extremely curious and relentless; I just do not give up. I am very good at trying a problem and, if I am unable to solve it, stepping away for a while before coming back to try again.
I have had many role models during my career. A huge component of success is your ability to find good mentors to help you address deficiencies that you may have. Be proactive and approach individuals you admire, so they can eventually become your network of mentors and a source of intellectual help when you need it.
To unwind, I run outside, swim, or play and dance with my two daughters.
Netz’s top tip
Explore various options without fear. Fewer and fewer people have linear career paths. Most of us stumble from place to place until we find our vocational calling. If you are interested in something, try it. The worst that can happen is you don’t like it and you just have to move on and find something else.
Do you have a question for Netz?
Write it in the comments box below and Netz will get back to you. (Remember, researchers are very busy people, so you may have to wait a few days.)
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