At KAIST, the Korea Advanced Institute of Science and Technology in South Korea, researchers have developed a new breath sensor that uses protein-encapsulated nanocatalysts to spot certain biomarkers of diseases. While the breath can hold a lot of information about what’s going on inside the body, the variety of gasses present and the large amount of water vapor make it very difficult to spot biomarkers present at concentrations approaching as low as a few parts per billion.
The new prototype device features sixteen sensors, each able to spot a specific chemical that is a signature of various health parameters. They rely on newly developed heterogeneous nanocatalysts, functionalized on metal oxide nanofiber sensing layers, that were build using protein templates that are 2 nanometers in size.
More details according to a KAIST announcement:
To overcome the current limitations, the research team utilized nanoscale protein (apoferritin) in animals as sacrificial templates. The protein templates possess hollow nanocages at the core site and various alloy catalytic nanoparticles can be encapsulated inside the protein nanocages.
The protein nanocages are advantageous because a nearly unlimited number of material compositions in the periodic table can be assembled for the synthesis of heterogeneous catalytic nanoparticles. In addition, intermetallic nanocatalysts with a controlled atomic ratio of two different elements can be achieved using the protein nanocages, which is an innovative strategy for finding new types of catalysts. For example, highly efficient platinum-based catalysts can be synthesized, such as platinum-palladium (PtPd), platinum-nickel (PtNi), platinum-ruthenium (PtRu), and platinum-yttrium (PtY).
The research team developed outstanding sensing layers consisting of metal oxide nanofibers functionalized by the heterogeneous catalysts with large and highly-porous surface areas, which are especially optimized for selective detection of specific biomarkers. The biomarker sensing performance was improved approximately 3~4-fold as compared to the conventional single component of platinum and palladium catalysts-loaded nanofiber sensors. In particular, 100-fold resistance transitions toward acetone (1 ppm) and hydrogen sulfide (1 ppm) were observed in exhaled breath sensors using the heterogeneous nanocatalysts, which is the best performance ever reported in literature.