A Cr₂O₃-doped graphene sensor for early diagnosis of liver cirrhosis: a first-principles study

Liver cirrhosis is among the leading causes of death worldwide. Because of its asymptomatic evolution, timely diagnosis of liver cirrhosis via non-invasive techniques is currently under investigation. Among the diagnostic methods employing volatile organic compounds directly detectable from breath, sensing of limonene (C₁₀H₁₆) represents one of the most promising strategies for diagnosing alcohol liver diseases, including cirrhosis. In the present work, by means of state-of-the-art Density Functional Theory calculations including the U correction, we present an investigation on the sensing capabilities of a chromium-oxide-doped graphene (i.e., Cr₂O₃-graphene) structure toward limonene detection. In contrast with other structures such as g-triazobenzol (g-C₆N₆) monolayers and germanane, which revealed their usefulness in detecting limonene via physisorption, the proposed Cr₂O₃-graphene heterostructure is capable of undergoing chemisorption upon molecular approaching of limonene over its surface. In fact, a high adsorption energy is recorded (∼-1.6 eV). Besides, a positive Moss-Burstein effect is observed upon adsorption of limomene on the Cr₂O₃-graphene heterostructure, resulting in a net increase of the bandgap (∼50%), along with a sizeable shift of the Fermi level toward the conduction band. These findings pave the way toward the experimental validation of such predictions and the employment of Cr₂O₃-graphene heterostructures as sensors of key liver cirrhosis biomarkers.