According to a report by Emergen Research, the global biosensor market is expected to grow annually by 7.3 percent between 2019 and 2027—from a value of $19.19 billion to $33.85 billion. A similar report by Fior Markets estimates a slightly higher growth rate, from $21.5 billion in 2019 to $41.29 billion by 2027. The reasons behind this projected growth are manifold, as the biosensor sector itself is diverse and the sensors fulfill a wide range of uses. As technological advancement in sensors progresses, their use can also become more practical, which in turn fuels growth of the sector. At the same time, the increase in the prevalence of diabetes and the emergence of the COVID-19 pandemic have both spurred market growth for biosensors.
Beyond widely recognized medical uses such as blood pressure and pulse monitors, biosensors are used in several other industries such as food and beverage, agriculture and biotechnology. Emergen Research defines a biosensor as a tool that senses and transmits knowledge about a life cycle that’s used by an observer or device to calculate and transform a biological reaction into an electrical signal for quick interpretation. As biosensors have become smaller, lighter and more portable, their prevalence has increased in a number of different settings. Various types of biosensors detect chemical substances in different ways using a transducer, which works by transforming a biological signal into something that can be analyzed and measured. Biosensors can be electrochemical, electrical, piezoelectric, optical, gravimetric and pyroelectric.
Emergen Research’s report shows electrochemical biosensors dominating the market by a share of 36 percent in 2019. This type of biosensor has low detection limits, a wide linear reaction range, stability and reproducibility, making it more widely used. The report anticipates that optical biosensors will have the fastest growth rate between 2020 and 2027 due to their flexibility when used in research analysis of receptor-cell interactions, fermentation control, kinetic analysis and equilibrium study.
Major Uses
In addition to being crafted as sensing devices, biosensors can be components within cameras, gyroscopes, accelerometers, optical and image monitors, micro-fluidics, thermometers and flow meters. Along with advancements in sensing technology, biosensor market growth has also been boosted by the coupling of artificial intelligence, the Internet of Things (IoT), cloud computing and nanotechnology. The onset of the COVID-19 pandemic has increased the demand for biosensors to not only monitor body temperature and heart rate but also to detect coronavirus contamination in pharmaceutical and agricultural products. The rise of the number of people diagnosed with diabetes in many countries and the evidence indicating the disease is a risk factor for COVID-19 mortality has also ramped up the need for biosensors. Diabetic patients often manage much of their treatment at home, and glucose biosensors that provide accurate blood sugar readings have become an essential device for these patients.
Other medical uses for biosensors include blood-oxygen monitors, fertility tests, cholesterol assays (including those that measure blood metabolites like lactate, creatine or urea), and sensors that can detect the presence of drugs or biochemicals in urine, blood, sweat or saliva. Some of these sensors can be used by patients at home, in outpatient care, in hospitals, in emergency rooms, or even in commercial settings that warrant certain medical or health testing. Biosensors are also being adopted in veterinary care as they provide noninvasive ways to monitor pets, livestock or wildlife for signs of disease.
In food and agricultural industries, biosensors can be used to detect the presence of allergens, antibiotics, contaminants, pathogens and moisture while measuring freshness and assessing the dietary composition of foods. These sensors can also be used to examine crops that have been exposed to natural disasters or bioterrorism.
According to Coherent Market Insights, the global cell culture monitoring biosensors market is expected to grow by 9.6 percent between 2020 and 2027. With the parallel growth in biotechnology for the development of vaccines, consumer products and foods, cell culture monitoring biosensors are also rising in demand. Used in both medical and commercial life science research labs, cell culture sensors track the growth of microbial cultures as well as nutritive inputs and gaseous outputs in the environments in which they are grown. This can give scientists a more hands-off approach to growing cultures and also allow for remote monitoring.
SARS-CoV-2 RapidPlex
Caltech researchers recently developed a COVID-19 test, RapidPlex, that uses an at-home, low-cost biosensor to test small amounts of blood or saliva and deliver results in under 10 minutes. This device stands to revolutionize the fight against the coronavirus because it could allow for more widespread testing of asymptomatic people, thereby reducing the chance that those individuals might unwittingly spread the disease to others.
Researcher Wei Gao, assistant professor at Caltech’s Department of Medical Engineering, used graphene—carbon in sheet form—to make the sensors. Using a plastic sheet etched by a laser produces a 3D graphene structure with small pores, creating a large surface area on the sensor, which increases sensitivity for high-accuracy detection of small volume compounds. The graphene structures are coupled with antibodies that are sensitive to proteins on the surface of the SARS-CoV-2 virus. RapidPlex also contains antibodies produced by the body to fight the virus, and chemical markers of inflammation that indicate the severity of infection.
“This is the only telemedicine platform I’ve seen that can give information about the infection in three types of data with a single sensor,” said Gao. “In as little as a few minutes, we can simultaneously check these levels, so we get a full picture about the infection, including early infection, immunity, and severity.”
Wearables
Biosensors that are worn on the body for prolonged detection are commonly used in the form of fitness trackers or remote medical safety devices that can, for example, measure body temperature to detect fever, which is often a symptom of COVID-19. One of the drawbacks of wearable sensors has been that they can cause skin inflammation or have detection sensitivity adversely affected by the presence of sweat, while also demonstrating a lack of breathability.
Researchers at Binghamton University recently came up with a possible solution to these challenges. A team led by Matthew S. Brown, a PhD student at the Department of Biomedical Engineering, studied polydimethylsiloxane (PDMS), a silicone material frequently used in biosensors because of its biocompatibility and softness. Generally, this material’s qualities as a solid, nonporous film can cause the problems of lack of breathability and sweat evaporation in biosensors.
The Binghamton team created a porous PDMS material by electrospinning, a method that creates nanofibers from electrical force. When the material was tested, it was found to act like components of the skin’s epidermis. It can also act as a dry adhesive to stay fixed to the skin. After seven days of use, biocompatibility and viability testing had better results compared to the traditional nonporous form of PDMS.
Powering Biosensors
Another challenge of biosensor technology is that the size and portability of sensors requires the use of battery power, which can be cumbersome and need recharging. Penn State University is leading a team of international researchers with the hope of developing a new generation of biosensors that can be powered by converting the biomechanical energy generated by the wearer into electrical energy that can power the device.
“In this particular review, we are looking at possible energy supply without the need for batteries and other components, so it’s of particular interest to create these energy harvesters for self-powered devices, or ones that could also be used to charge up a battery,” said Larry Cheng, Penn State professor in the Department of Engineering Science and Mechanics.
The team is looking both at devices that can harvest energy and ones that can power themselves. “It can serve as a sensor directly because it can harvest energy, so it can provide the capability to monitor the motion—for example, the heartbeat—or whatever the sensor is applied to, and then it can transmit that information from the environment, or from the body, so it can be analyzed,” said Cheng.
Development of such devices hinges on using stretchable piezoelectric materials as they can accumulate electrical charges. The stretchable nature would allow them to move smoothly along with human tissues. Although human movement has created a challenge for wearable biosensors in the past, these would capture some of that mechanical energy as a power source.
However, the research efforts won’t stop at mere wearable biosensors. The team wants to take biosensors a step further—implanting them inside the body. According to Cheng, over the last decade the development of piezoelectric materials has advanced to the point where they are flexible and impervious enough to withstand conditions inside the body, while remaining sensitive enough to detect minute changes to heartbeats or respiration, for example. Beyond this, the team has also set its sights on sensors that can harvest energy from the organs or tissues they are monitoring such as collecting energy from heartbeats and then transmitting data about heart function.
“That’s the amazing thing about these devices. People think that these types of motion are very minimal and don’t think about harvesting this energy,” said Cheng. “It was in the past decade or two when people began to see the possibilities to generate rather large signals from these movements through the high-efficiency circuits and also to use the high-efficiency rectifying circuit, which would consume a lot of energy if it isn’t designed correctly.”