Sensor platform uses nanopore ‘speed cameras’ to pinpoint gases in complex mixtures

From the analysis of breathing to explosive detection, many applications require reliable electronic “noses”. Unfortunately, current technology is often absent. This is why the researchers of Ku Leuven have developed a flexible sensor platform which detects not only the gases, but also records their speed, like a speed camera.

Technology, published in Nature communications And has since been patented, measures how fast the molecules move through a special nanomateriau. This opens the door to a wide range of applications.

Traditional chemical sensors generally measure the quantity of specific substance that adheres to a surface. But air contains hundreds of volatile organic compounds (VOCs), often in low concentrations and all mixed together. To make things even more complex, water vapor is often a thousand times more abundant than target substances, which makes many sensors difficult to take precise measurements. The result: bad reliability and precision.

The new Ku Leuven sensor platform uses metal-organic frames (MOF): materials with a network of nanopores which are all exactly the same size. These act like cameras at molecular speed. When the gas molecules move through the pores at a slightly high temperature, they do so at different specific speeds depending on their structure. This speed acts as a fingerprint. By measuring speed, researchers can distinguish between different gases, even in difficult conditions where traditional sensors fail.

“You can compare our approach to speed monitoring for molecules,” explains Margot Versreken, bioscience engineer and postdoctoral researcher of the Amelolot research group in Ku Leuven. “We are not only looking at how many molecules move in nanopores, but also to speed differences. We call this kinetic selectivity. This additional information makes all the difference.”

Scalable platform

What makes the Ku Leuven approach unique is that it is an evolutionary platform. “By adjusting the metal-organic frame, we can adapt the sensor to specific gases without changing the underlying technology,” explains Versreken. “The system remains compact, energy efficient and very efficient. Even in wet environments or with complex gas mixtures and low concentrations, it surpasses the commercial electronic nose.”

A patent application was subjected to the specific sensor structure, as there is a wide range of potential applications for this technology. Think of a breath test for the early diagnosis of diabetes; or detect leaks in the chemical industry and defects in Li-ion batteries, monitoring indoor or exterior air quality; Or follow the freshness of fruits and vegetables in storage. Even explosives or hidden drugs can be detected more quickly and precisely with this technology. Due to its modular design, the sensor can be adapted to each task: choose the right MOFs and the platform makes it work.

“This is not a sensor designed for a specific task, but a modular platform”, underlines Versreken. “By selecting the right MOF or the combination of MOF, you can adapt the sensor to what you want to detect. This flexibility makes our platform suitable for a wide range of sectors, safety health care.”

With this research, Margot Versreken won the Belgian edition of Falling Walls, an international scientific communication competition. In November, it will represent Belgium in the Berlin World Final, competition with young researchers from more than a hundred countries.