In silico study of the sensing properties of C18, B9N9, and Al9N9 nanorings for diabetes monitoring via indole detection in exhaled breath

Abstract Detecting indole in exhaled breath has immense promise for non-invasive diabetes monitoring. Here, we pursued a computational evaluation of the performance of C 18 , B 9 N 9 , and Al 9 N 9 nanoring structures as sensors for indole. The evaluated processes included Density Functional Theory calculations, Quantum Theory of Atoms in Molecules analysis, Non-Covalent Interaction studies, and UV–Vis spectral analysis, to interpret electronic interactions and adsorption between indole and sensors. The findings suggested that B9N9 showed the most significant interaction with indole, with the highest adsorption energy (− 20.71 kcal/mol) and longest recovery time (1.54 × 10 3 s), indicating its superior sensitivity. Al 9 N 9 performed moderately, while C18 had the lowest interaction with indole. Furthermore, B 9 N 9 showed a significant increase in electrical conductivity (2.81 × 10 9 –2.88 × 10 9 S/m), making it an attractive candidate for electrochemical sensors. In the UV–Vis spectra, Al 9 N 9 @Indole showed a significant red shift of 87 nm, going from 376 to 463 nm. This change shifts it from the UV range into the visible spectrum, enabling a noticeable color change. Therefore, B 9 N 9 is well-suited for electrochemical sensing due to its high sensitivity and fast response. Al 9 N 9 is notable for its visible optical response, which makes it suitable for colorimetric sensing when indole is present.