Tin oxide fibres provide key to exhaled-breath diagnostic sensor

The sensor works through the arrangement of hierarchical tin oxide (SnO₂) fibres that are assembled from wrinkled thin SnO₂ nanotubes.

Il-Doo Kim, Associate Professor of Materials Science and Engineering Department at the Korea Advanced Institute of Science and Technology (KAIST), and his research team have detailed their research in a paper entitled, Thin-Wall Assembled SnO₂ Fibres Functionalized by Catalytic Pt Nanoparticles and their Superior Exhaled Breath-Sensing Properties for the Diagnosis of Diabetes, in Advanced Functional Materials.

In the paper, the research team presented a morphological evolution of SnO₂ fibres, dubbed micro phase-separations, which takes place between polymers and other dissolved solutes when varying the flow rate of an electrospinning solution feed and applying a subsequent heat treatment.

The morphological change results in nanofibres that are shaped like an open cylinder inside which thin-film SnO₂ nanotubes are layered and then rolled up.

A number of elongated pores ranging from 10nm to 500nm in length along the fibre direction were formed on the surface of the SnO₂ fibres, allowing exhaled gas molecules to easily permeate the fibres.