Highlights
- Developed cerium-doped ZnO thin-film sensors targeting acetone and ethanolamine, biomarkers for diabetes and liver disorders.
- Grain size decreased and optical band gap widened as cerium-dopant concentration increased.
- 0.004 M and 0.008 M cerium-doped films gave the best response to acetone and ethanolamine respectively, with swift response and recovery.
Abstract
Cerium-doped zinc oxide (ZnO) thin films were deposited on glass by spray pyrolysis to develop a chemiresistive breath sensor for acetone and ethanolamine, biomarkers linked to diabetes mellitus and liver disorders respectively. X-ray diffraction confirmed a polycrystalline hexagonal ZnO structure across all cerium-dopant concentrations, and increasing cerium content reduced average grain size while widening the optical band gap. Films with 0.004 M and 0.008 M cerium dopant gave the best room-temperature response to acetone and ethanolamine respectively, with swift response and recovery, suggesting a non-invasive, low-cost route to disease-linked breath analysis.
Research summary
Breath analysis is an appealing, non-invasive way to screen for disease because certain volatile compounds in exhaled breath track with specific conditions — elevated acetone with diabetes mellitus, and abnormal ethanolamine with liver disorders such as primary carcinoma. This study develops cerium-doped ZnO thin-film sensors aimed at detecting these two biomarkers at room temperature.
What the study examined
- Ce-doped ZnO thin films deposited on glass by spray pyrolysis, with cerium concentration varied
- Crystal structure by X-ray diffraction, confirming polycrystalline hexagonal wurtzite ZnO
- Grain size and optical band gap changes with increasing cerium-dopant concentration
- Room-temperature sensing response, response time, and recovery time toward acetone and ethanolamine vapors
Main findings
Cerium doping produced a consistent trend: as dopant concentration increased, average grain size decreased and the optical band gap widened. Sensing tests showed that different doping levels favored different target gases — a film with 0.004 M cerium gave the best response to acetone, while a film with 0.008 M cerium gave the best response to ethanolamine, both with fast response and recovery times.
The acetone-sensitive film could detect concentrations down to about 1 ppm, in the range relevant to distinguishing diabetic from non-diabetic breath profiles.
Why it matters
By showing that cerium-doping level can be tuned to favor one breath biomarker over another, the study points toward low-cost, portable, chemiresistive sensors that field medical staff could use as a rapid first-pass indicator for conditions like diabetes mellitus or liver disorders, ahead of confirmatory clinical testing.
Citation
K. Arockia Jayalatha, E. Vignesh, Prabakaran Shankar, G. K. Mani, K. Jayanth Babu, J. B. B. Rayappan. Nanostructured Cerium-Doped ZnO Thin Film: A Breath Sensor. Ceramics International 42 (2016) 18289-18295.
