Realizing the diagnosis of lung cancer at an inchoate stage is significant to get valuable time to conduct curative surgery. In this work, we relied on a density functional theory (DFT)-proposed Ru–SnS₂ monolayer as a novel, promising biosensor for lung cancer diagnosis through exhaled gas analysis. The results indicated that the Ru–SnS₂ monolayer has admirable adsorption performance for three typical volatile organic compounds (VOCs) of lung cancer patients, which therefore results in a remarkable change in the electronic behavior of the Ru-doped surface. As a consequence, the conductivity of the Ru–SnS₂ monolayer increases after gas adsorption based on frontier molecular orbital theory. This provides the possibility to explore the Ru–SnS₂ monolayer as a biosensor for lung cancer diagnosis at an early stage. In addition, the desorption behavior of three VOCs from the Ru–SnS₂ surface is studied as well. Our calculations aim at proposing novel sensing nanomaterials for experimentalists to facilitate the progress in lung cancer prognosis.

Lung cancer has received considerable attention in recent years due to its high mortality. The difficulty in awareness of such disease can be attributed to its strong insidiousness during the early stage. Therefore, the prognosis of lung cancer becomes significant so as to nip this disease in the bud. In this paper, the Rh-doped CNT-based biosensors were introduced to realise the diagnosis of lung cancer through detecting the exhaled gas of possible patients. The adsorption property and sensing mechanism of Rh-CNT towards two kinds of mainly typical gases of lung cancer, namely, C₆H₆ and C₆H₇N, were analysed based on density functional theory, aiming at evaluating the potential application of such material to be gas sensors. The results indicated that the Rh-CNT not only has good adsorption towards such two gases but also obvious conductivity increase when interacted with any of them, while presents insensitivity upon the common exhaled gas, CO₂. We suggest the Rh-CNT be prepared as biosensors applied in the field of lung cancer pre-diagnosis that can be used in our daily life without pain and complex clinical examination.

At present, reports on the arc interruption and decomposition behavior of a C ₄ F ₇ N/air gas mixture especially the biosafety of its by‐products are limited. Herein, a 57% C ₄ F ₇ N/43% air gas mixture was employed as an arc‐quenching medium to conduct 200 breaking tests on a load switch (630 A/24 kV). The arc interruption and decomposition behavior of the gas mixture were evaluated, and the biosafety of the decomposition products was assessed based on an acute inhalation toxicity test. It was found that the average arcing time of the 200 breakings was about 10.1 ms and that breakings were basically completed at the zero‐crossing of the second or third current half‐cycle. The gas mixture after breaking decomposed dramatically (the C ₄ F ₇ N content decreased by 75.6%), generating a large number of gaseous by‐products (CO, CF ₄ , C ₂ F ₆ , C ₃ F ₈ , CF ₃ CN, C ₄ F ₈ , CO ₂ , C ₄ F ₁₀ N ₂ , C ₃ F ₆ , C ₂ N ₂ , etc.) as well as solid by‐products (carbon particles). The lethal concentration of 50% (LC50, 4 h) of C ₄ F ₇ N/air after 200 breakings was 31 ppm (male mice) and 34 ppm (female mice), respectively, and the toxicity was classified as Grade 1. In general, C ₄ F ₇ N has an arc interruption capability, albeit weaker than that of SF ₆ under the same conditions. After breaking, the C ₄ F ₇ N gas mixture has a relatively high acute inhalation toxicity, and relevant safety protection measures for research or operation personnel are strictly needed.

Nanosensor-based patient exhaled breath detection is a practical and effective way to detect lung cancer early. In this paper, a Ru-doped MoS₂ monolayer (Ru-MoS₂) is proposed as a promising novel biosensor based on first-principles theory for the detection of three typical early stage lung cancer exhaled volatile organic compounds, namely, C₃H₄O, C₃H₆O, and C₅H₈. Replacement of a S atom in the MoS₂ monolayer with a Ru dopant atom to form a stable Ru-MoS₂ monolayer with a binding energy of -4.78 eV is further demonstrated by the thermostability and chemical stability analysis as well as improving the adsorption performance of the system for three VOCs. The adsorption configuration structures, adsorption properties, and electronic behavior of the Ru-MoS₂ monolayer are investigated by electron deformation density and density of states analysis to gain a comprehensive understanding of the physicochemical properties as sensing material. The results show that the adsorption energies of the Ru-MoS₂ monolayer for C₃H₄O, C₃H₆O, and C₅H₈ are 3.42, -1.53, and -2.80 eV, respectively, all of which are chemisorption with excellent adsorption performance. The sensitivities for the three VOCs could be up to 1.09, 140.50, and 5.90, respectively, and the band structure and work function further elucidate the sensing mechanism of the Ru-MoS₂ monolayer as a resistive gas sensor. The type and concentration of these exhaled breaths may reflect changes in the patient's physiological and biochemical status and may serve as a probe for the diagnosis of lung cancer. The results in this work could provide a guidance for researchers to explore the practical applications in the early diagnosis of lung cancer by gas sensors.

Using the first-principles theory, the geometric and electronic properties of the Ru-doped PtTe₂ (Ru-PtTe₂) monolayer, and its sensing performance for three VOCs biomarkers, namely, 2-propenal (C₃H₄O), acetone (C₃H₆O) and isoprene (C₅H₈), were analyzed, to expound its potential for exhaled breath analysis and diagnosis of lung cancer. It was found that the Ru-substitution on the surface of the pristine PtTe₂ surface with a Te atom is energy-favorable, with the formation energy of −1.22 eV. Upon adsorption of the three VOC gas species, chemisorption was identified with the adsorption energies of −1.72, −1.12 and −1.80 eV for C₃H₄O, C₃H₆O and C₅H₈, respectively. The Ru-doping results in a strong magnetic property for the PtTe₂ monolayer, whereas the gas adsorption eliminates this magnetic behavior. The electronic properties reveal the sensing mechanism of the Ru-PtTe₂ monolayer for gas detection, and the bandgap change indicates its admirable positive sensing response for the three gas species. Therefore, we conclude that the Ru-PtTe₂ monolayer is a promising sensing material to realize the diagnosis of lung cancer through exhaled gas detection, with a remarkable decrease in its electrical conductivity. This work paves the way for further exploration of the PtTe₂-based gas sensor for early diagnosis of lung cancer, and we hope that more sensing materials can be investigated using the PtTe₂ monolayer.

A lot of useful information is contained in the human breath gases, which makes it an effective way to diagnose diseases by detecting the typical breath gases. This work investigated the adsorption of typical lung cancer breath gases: benzene, styrene, isoprene, and 1-hexene onto the surface of intrinsic and Ni-doped single wall carbon nanotubes through density functional theory. Calculation results show that the typical lung cancer breath gases adsorb on intrinsic single wall carbon nanotubes surface by weak physisorption. Besides, the density of states changes little before and after typical lung cancer breath gases adsorption. Compared with single wall carbon nanotubes adsorption, single Ni atom doping significantly improves its adsorption properties to typical lung cancer breath gases by decreasing adsorption distance and increasing adsorption energy and charge transfer. The density of states presents different degrees of variation during the typical lung cancer breath gases adsorption, resulting in the specific change of conductivity of gas sensing material. Based on the different adsorption properties of Ni-SWCNTs to typical lung cancer breath gases, it provides an effective way to build a portable noninvasive portable device used to evaluate and diagnose lung cancer at early stage in time.