City Research Online

Abstract

It has been observed that human breath contains a unique profile of volatile organic compounds (VOCs) that may serve as disease biomarkers for understanding health issues. Breath VOCs are normally generated by the body's metabolic activity, and changes in their concentrations are useful for diagnosing target diseases. Approximately thousands of VOCs, together with respiratory droplets, are found in the exhaled breath. Each VOC is associated with a distinct condition, and therefore, the breath analysis plays a key role in providing health-related information in a non-invasive manner. VOC sensing is generally performed by integrating VOC-sensing materials along with various sensing platforms (e.g., an electrode, optical fibre, QCM) to specifically detect target VOCs. Among several types of sensing materials, titanium dioxide (TiO2) with low to high dimensional characteristics shows calibrated sensing performance that scales with material dimensionality, leading to an increased number of active sites for VOC adsorption. This review provides a fundamental understanding of TiO2, including its types, sensing methods, and applications in VOC sensing. Furthermore, this review includes comprehensive summary tables of the recent literature, compares the advantages and limitations of different TiO2 nanostructures, and outlines the major challenges and potential solutions for their clinical translation.

Publication Type:	Article
Additional Information:	© 2026 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/
Publisher Keywords:	Titanium dioxide, Breath analyzer, Volatile organic compounds, Biomarker, Health condition, Metal oxides, Gas sensing
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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