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Biosensors are increasingly used everywhere from medical to environmental monitoring – and some IEC Standards for this fast-evolving area already exist.
The era of bio-digital convergence is upon us two decades after it was first predicted, and the merging of biology and digital technology is accelerating thanks to genomics, the growth of artificial intelligence (AI) and the development of quantum-based encryption.
Today, we can store information in our DNA by digitally interacting with it. Technology implanted within the human brain can help those with devastating spinal cord injuries to walk again and might soon return sight to those who have lost it. Meanwhile, biosensors of all types are emerging to help humanity combat disease and a plethora of environmental challenges.
Biosensors have been around for decades. They are devices that can “detect the presence or concentration of a biological analyte, such as a biomolecule, a biological structure or a microorganism” and some of the most famous iterations include lateral flow tests, also known as rapid tests, that include the home pregnancy test and continuous glucose monitors for diabetes management.
Biosensors are well established in the medical field for point-of-care testing (POCT) and rapid diagnostics. The manufacturing of this type of device scaled rapidly during the COVID pandemic, which also saw the commercialization of genomics-based biosensing through DNA sequencing, working alongside polymerase chain reaction (PCR), based on the enzymatic replication of DNA.
According to global newswire SNS Insider, the global point-of-care diagnostics market is expected to reach USD 91,47 billion by 2032, while the market for point-of-care biosensors is expected to grow towards USD 29,5 billion by 2032, driven by ageing populations and sedentary lifestyles in the developed world, expanding population sizes in the developing world and waves of epidemics linked to climate change.
These healthcare demands are shifting diagnostics away from laboratories directly to the point of care. But while biosensor technologies at point of care have reached maturity, they are still hindered by the accuracy of their readings and the sensitivity and specificity of their bioreceptors. As biosensors become smaller, miniaturizing them without sacrificing lab-grade quality remains a challenge.
Scientists are also exploring the potential of in-vivo, or implanted, biosensors and their limitations, including rejection, invasive procedures and ethics. A team at Harvard recently unveiled a new coating for implantable devices that prevents biofouling by bacteria, cells and other biofluids on the sensor surface, reducing the risk of malfunction and “foreign-body responses” or rejection.
A team from Beijing recently announced the development of an epidermal serine sensing patch to allow direct sampling and in-situ quantification of epidermal serine to monitor atopic dermatitis, while the difficult task of real-time on-demand potassium monitoring is being tackled by a Canadian start-up to better manage cardio-kidney-metabolic disease. And in the US, research around AI-driven biosensing for mental health monitoring is ongoing.
In Switzerland, proteomics, the large-scale study of proteins and their function, is capturing the imagination of experts like Dr Til Schlotter. “Single molecule analysis is the future of biosensors”, says Schlotter, who is the co-founder and CEO of a deep tech start-up out of ETH Zurich. “Proteins are the workhorses of any biological system; all the communication in your body works with proteins, but they cannot be analyzed at single molecule level yet. The goal for us is to bring single molecule protein analysis to the market, which nobody can do yet.” This would benefit not only drug development, but also food contamination analysis, plant engineering and even extraterrestrial discoveries.
According to SNS, the overall biosensors market size is expected to reach USD 56,54 billion by 2032, and while many applications beyond healthcare are still at the research stage, they show great promise, especially for detecting water quality. The dangers of per- and polyfluoroalkyl substances (PFAS) in drinking water are now recognized worldwide and being addressed through the development of genetically-encoded biosensors. A team at Qingdao University in China has also developed a self-powered, three-component biosensor that can make water safe to drink in developing countries.
Portable biosensors for environmental DNA (eDNA) detection could support marine conservation by monitoring the health of coral reefs, while in-vivo biosensors could help track neural activity, such as sleep, in freely behaving animals.
Microbial biosensors such as E. coli are also promising. The biochemical response of E. coli has been used to detect the presence of heavy metals in water, while recently, a research team from Denmark, Germany and Israël created a strain of E. coli to be used for the successful detection of phytoplankton blooms through the glycolate they release. These microbial biosensors also allowed for the detection of the key enzymes involved in synthetic CO₂ fixation pathways as well as in carbon conserving ones, which are critical for one-carbon biomanufacturing applications, according to postdoctoral researcher Enrico Orsi.
“Our sensors allow enzyme testing inside the cell,” says Orsi. “It is not the first time bacteria are used as biosensors, but we are focusing on a special type of biosensor which cannot grow unless the molecule of interest is present.”
The IEC 60747-18 series of standards provides reference measurement protocols for each stage of converting a biological signal into digital information. By enabling calibration and evaluation of potential deviations at each step, these standards aim to support the widespread adoption of highly consistent, reliable biosensors.
JongMuk Lee, biosensor expert in the IEC technical committee which publishes standards for sensors, IEC TC 47, and CEO of biotech startup SOL Inc, explains that the IEC 60747-18 series defines evaluation and test methods specifically for lens-free complementary metal-oxide-semiconductor (CMOS) photonic array sensors (CPAS), addressing various performance characteristics. Lens-free CPAS, which differ significantly from conventional CMOS image sensors used in traditional cameras, are a key component in a promising high-resolution technology called lens-free digital inline holographic microscopy (DIHM) systems. These systems are ideal for image-based analysis and point-of-care diagnosis in resource-limited settings due to their portability and low manufacturing cost.
“In lens-free CPAS, biological samples are placed directly above the pixel array, or biological reactions occur directly on it,” explains Lee. “Given that the pixel dimensions may be larger or smaller than the biological targets, such as cells, bacteria, proteins or DNA, it becomes critical to ensure that the sensor can reliably capture the interactions at the single-pixel level.”
According to Lee, TC 47 plans to continue expanding the IEC 60747-18 series. “As biotechnological experiments and pharmaceutical research in space become increasingly common, the need for evaluating the performance of lens-free CPAS under extraterrestrial conditions is also growing,” he says. “Standards for such use cases are under consideration.”
And given the critical importance of data security in biomedical and healthcare applications, the integration of encryption features such as quantum random number generation (QRNG or QRBG) within the CPAS itself is envisioned. “Future standards may address the incorporation of cryptographic logic or even AI models directly into the sensor hardware,” he concludes.