Nanotube Sensors Promise Revolution in Health Monitoring and Hormone Detection
Researchers are making strides toward more precise healthcare sensors thanks to advancements in nanomaterials. Scientists at the University of Turku, Finland, have developed sensors using single-wall carbon nanotubes, which could significantly improve continuous health monitoring and the detection of subtle biological changes, such as fluctuations in female hormone levels.
These sensors are fabricated from single-wall carbon nanotubes, a nanomaterial composed of a single atomic layer of graphene. A notable challenge in nanotube development has been the manufacturing process, which produces a mixture of conductive and semi-conductive nanotubes with varying chiralities—the way the graphene sheet is rolled into a cylindrical structure. The electrical and chemical properties of a nanotube are largely determined by its chirality, making it crucial to distinguish between them.
Han Li, a Collegium Researcher in materials engineering at the University of Turku, has developed methods to separate nanotubes based on their chirality. In this study, researchers successfully differentiated between two carbon nanotubes with nearly identical chirality, identifying their distinct electrochemical properties. “Although the difference in the chirality of the nanotubes is very slight, their properties are very different,” explained Ju-Yeon Seo, Doctoral Researcher, University of Turku.
Accuracy and Sensitivity for Sensors
By purifying and isolating the nanotubes, researchers were able to analyze their differences as sensor materials. While nanotubes are often used in hybrid sensors with other surfactants, this study focused on sensors made solely from nanotubes. The team also exerted precise control over nanotube concentration, which enabled a direct comparison of different chiralities. The study highlighted that one type of nanotube (6.5) was more effective at adsorbing dopamine than another (6.6).
This is especially important for detecting substances present in very low concentrations. Seo added, “The result is significant because by being able to precisely control the properties of carbon nanotubes we can fine-tune the ability of the sensor material to detect changes in specific substances.”
Currently, sensors can monitor blood glucose levels, but University of Turku researchers aim to develop materials to detect dramatically lower concentrations of other biological markers. Associate Professor Emilia Peltola, of Materials Engineering at the University of Turku, said, “The molecules that we are interested in, such as female hormones, are present in the body in concentrations that are millions of times lower than glucose.” Greater accuracy in biosensors is needed to study hormone fluctuations.
This research is the first to demonstrate the influence of nanotube chirality on a sensor’s electrochemical response. Future studies may use computational models to identify the optimal chirality for detecting particular molecules. The Materials in Health Technology group at the University of Turku is focused on understanding how different material surfaces interact in biomedical applications. They aim to develop next-generation sensor technologies that are not only more sensitive and accurate but also maintain functionality in biological environments.
Journal Reference: Seo, J.-Y., et al. (2025) Single-chirality single-wall carbon nanotubes for electrochemical biosensing. Physical Chemistry Chemical Physics. doi.org/10.1039/d4cp04206a.
