Electrochemical studies on doped SnO2 nanocomposite for selective detection of lung cancer biomarkers

Lung cancer (LC) is one of the major disease causes for cancer-related mortality. The detection of volatile organic compounds (VOCs) as lung cancer biomarkers will be useful for early stage detection. Hence, the development of electrochemical sensors to detect acetone and toluene as biomarkers below the allowed permissible limit in a sensitive and selective manner is essential. In this study, transition metal ion doped SnO2 nanocomposites have been developed by the hydrothermal method and used for the selective detection of LC biomarkers. The morphologies, structures, and chemical compositions of synthesized materials were studied using field-emission scanning electron microscopy (FESEM), x-ray diffraction, UV–visible spectroscopy, and Fourier transform infrared spectroscopy. The UV–visible study revealed that the doping of metal ions reduces the bandgap, and FESEM analysis showed a spherical like morphology that improves the adsorption sites on materials. Furthermore, cyclic voltammetry and electrochemical impedance spectroscopy revealed that the doping of transition metal ions improves the charge transfer ability and electrochemical activity of nanocomposites. The selective chemisorption of lung cancer biomarkers on metal-doped SnO2 nanocomposites helps in achieving a superior response with a broad linear detection range (20–100 ppb for toluene and 1–1000 ppb for acetone). In addition, the limit of detection achieved for toluene (1 ppb) and acetone (0.1 ppb) is well below the permissible limit for lung cancer patients. The fabricated nanocomposite is found to be highly selective toward acetone and toluene with a selectivity factor ranging from 1.8 to 12 and 6.6 to 10, respectively, as compared with other VOCs.