Atomically thin sensors poised to transform electronic biosensing

Researchers from the University of Massachusetts Amherst, the University of Strasbourg, and the University of California Los Angeles have highlighted the potential of two-dimensional electronic biosensors in a recent publication in Nature Reviews Electrical Engineering. These sensors, which utilize materials such as graphene, are poised to revolutionize the detection of disease markers, viral variants, and stress hormones, among other applications. Graphene, a single layer of carbon atoms arranged in a honeycomb lattice, remains a cornerstone of this field due to its exceptional electrical and mechanical properties.

Two-dimensional materials, including graphene, possess unique characteristics that make them ideal for biosensing. Their atomically thin structure allows every atom to be exposed to the environment, enabling direct interaction with biomolecules. This interaction perturbs the charge flow in the material, allowing for highly sensitive detection without the need for amplification or labeling. Graphene-based transistors have demonstrated the ability to detect a range of biological markers, including pH changes and viral particles, with high sensitivity.

Beyond graphene, materials such as transition-metal dichalcogenides, black phosphorus, and MXenes offer additional functionalities. Transition-metal dichalcogenides, for instance, have semiconducting bandgaps that enable different operational modes, enhancing the selectivity and sensitivity of biosensors. These materials have been used to detect nucleic acids and proteins with remarkable precision. The diversity of two-dimensional materials allows for tailored biosensing solutions, although challenges remain in standardizing performance metrics across different materials and devices.

The development of biosensors also hinges on effective biofunctionalization strategies. The choice of chemistry to attach biological receptors to sensor surfaces affects the stability and performance of the devices. Covalent and non-covalent approaches each have their advantages and limitations, influencing the sensor's durability and sensitivity. Emerging techniques, such as CRISPR-Cas9 immobilization and DNA origami, are expanding the possibilities for molecular selectivity in biosensing applications.

Despite significant advancements, the field faces challenges in achieving selectivity, stability, and reproducibility. Variability in material properties and fabrication processes can lead to inconsistent sensor performance. The authors emphasize the need for standardized testing protocols to ensure reliable comparisons across different biosensing technologies. Additionally, biocompatibility and scalability are critical for transitioning these sensors from laboratory settings to practical applications in healthcare and environmental monitoring.

The potential applications of two-dimensional electronic biosensors are vast, ranging from wearable health monitors to implantable diagnostic devices. As the field progresses, the focus will shift towards overcoming remaining obstacles in selectivity and stability, paving the way for the integration of these sensors into the Internet of Medical Things. By leveraging the unique properties of two-dimensional materials, researchers aim to develop reliable biosensing technologies that can be widely adopted in clinical and consumer settings.