Graphene gas sensor towards cancer prediction with photocatalyst

Cancer is one of the leading causes of mortality worldwide[1]. Owing to its rapid progression and high fatality rate, early detection and diagnosis are crucial. Volatile organic compounds (VOCs), carbon-based metabolites present in human breath, can serve as biomarkers for cancer (e.g., acetone, ethanol, toluene) [2]. Conventional detection techniques, such as gas chromatography–mass spectrometry, are effective but rely on bulky, non-portable instrumentation and are prohibitively expensive. By contrast, graphene-based sensors provide a low-cost and portable alternative for gas sensing, owing to graphene’s unique physical (high surface-to-volume ratio) and electrical (excellent carrier mobility) properties [3,4]. However, previous studies have shown that graphene produced via transfer-free methods[5] exhibits a weak response to VOCs, highlighting the need for performance enhancement. Photocatalysts, such as TiO₂, can accelerate the oxidation of VOCs under ultraviolet (UV) light[6,7]. Photocatalytic oxidation of VOCs, therefore, holds considerable potential for improving the sensitivity and selectivity of graphene-based gas sensors.

In this project, we propose employing spark ablation technology to deposit photocatalyst nanoparticles onto our graphene chemoresistors/GFETs platform. Spark ablation is a low-cost technique for generating controllable nanoparticles from electrodes, capable of producing particles from more than half of the known elements [8]. By carefully selecting the photocatalyst material and optimising nanoparticle deposition parameters, this project aims to develop a highly sensitive and selective VOC sensor at low cost. The outcomes of this work could contribute to advances in healthcare diagnostics, opening new opportunities for accessible and personalised healthcare.

Assignment

• Literature review of photocatalyst and graphene-based VOC (ethanol, toluene) sensors.
• Select a photocatalyst and UV source towards VOC sensing.
• Spark ablation process optimisation towards selected material.
• Nanoparticle analysis with material characterisation technologies (e.g. SEM, AFM, etc.).
• Fabricate the graphene sensor platform with photocatalyst material.
• Electrical characterisation and gas sensing measurements with our sensing platform.

Requirements

• Creative and passionate MSc students.
• Background in microelectronics, material science, biomedical engineering, or nanotechnology.
• Able to work independently.
• Fluent in English.

References:
[1] R. L. Siegel, T. B. Kratzer, A. N. Giaquinto, H. Sung, and A. Jemal, “Cancer statistics, 2025,” CA: A Cancer Journal for Clinicians, vol. 75, no. 1, pp. 10–45, Jan. 2025, doi: 10.3322/caac.21871.
[2] Y. Gao, B. Chen, X. Cheng, S. LiuD, Q. Li, and M. Xi, “Volatile organic compounds in exhaled breath: Applications in cancer diagnosis and predicting treatment efficacy,” Cancer Pathogenesis and Therapy, Jan. 2025, doi: 10.1016/j.cpt.2024.12.004.
[3] Y. Y. Broza, R. Vishinkin, O. Barash, M. K. Nakhleh, and H. Haick, “Synergy between nanomaterials and volatile organic compounds for non-invasive medical evaluation,” Chem. Soc. Rev., vol. 47, no. 13, pp. 4781–4859, 2018, doi: 10.1039/C8CS00317C.
[4] F. Schedin et al., “Detection of individual gas molecules adsorbed on graphene,” Nature Materials, vol. 6, no. 9, pp. 652–655, Sep. 2007, doi: 10.1038/nmat1967.
[5] S. Vollebregt et al., “A transfer-free wafer-scale CVD graphene fabrication process for MEMS/NEMS sensors,” in 2016 IEEE 29th International Conference on Micro Electro Mechanical Systems (MEMS), Jan. 2016, pp. 17–20. doi: 10.1109/MEMSYS.2016.7421546.
[6] S. Rouhani and F. Taghipour, “Photocatalytic oxidation of volatile organic compounds (VOCs) in air using ultraviolet light-emitting diodes (UV-LEDs),” Chemical Engineering Science, vol. 272, p. 118617, May 2023, doi: 10.1016/j.ces.2023.118617.
[7] S. Wang, H. M. Ang, and M. O. Tade, “Volatile organic compounds in indoor environment and photocatalytic oxidation: State of the art,” Environment International, vol. 33, no. 5, pp. 694–705, Jul. 2007, doi: 10.1016/j.envint.2007.02.011.
[8] D. P. Debecker et al., “Spark ablation: a dry, physical, and continuous method to prepare powdery metal nanoparticle-based catalysts,” Chem. Commun., vol. 60, no. 79, pp. 11076–11079, 2024, doi: 10.1039/D4CC03469D.

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Last modified: 2025-12-09