Ultrathin borophene based biosensor for early detection of alzheimer's disease and pancreatic cancer biomarkers: Acumen from DFT

Early diagnoses of Alzheimer's disease (AD) and pancreatic cancer (PC) are crucially important for the start of prognosis seeking the curing and saving of human lives. The present investigation aims to computational design materials having high selectivity towards the detection AD and PC biomarkers. Density functional theory (DFT) is explored to investigate the selective adsorption of pristine and metal-doped β12-borophene towards the volatile organic compounds (VOCs), related to AD or PC and well-known to exist in the exhaled breath of patients. Six VOCs were considered in our study; namely, (i) Three AD VOCs: 2,3-Dimethylheptane (2,3-DMH), Butylatehydroxytoluene (BHT), and Pivalic Acid (PVA); and (ii) Three PC VOCs: 2-pentanone (2p-none), 4-ethyl-1–2dimethyl benzene (4E-1,2-DMB), and n-nonanol (n-nonal). Pristine β12-borophene demonstrated selective adsorptions towards the six VOCs compared to the interfering air molecules (N₂, O₂, CO₂, H₂O) with adsorption energies at order [-0.85, -0.45] eV compared to [-0.20, -0.10], respectively. To enhance further the adsorption energies of VOCs and consequently the selectivity, the embedment of metal atoms in the small pores of β12-borophene monolayer has been explored. It is found that small-sized atoms such as alkali metal (Li) can be stably accommodated and yield large dipole moments to enhance the van der Waals interactions. For instance, using single-atom catalyst (SAC) of Li, the adsorption energies with VOCs were enhanced to become of magnitudes at order of 1.0 – 1.6 eV. While the magnetic state was maintained robust paramagnetic, the strong interactions with VOCs affected the recovery time to become huge. The SAC-Li doped β12-borophene can be proposed as candidate material for a platform of disposable nano biosensor with high sensor response to detect AD and PC biomarkers and consequently to contribute to the early diagnosis of these hazardous diseases. PACS Numbers: 31.15.E-, 68.43.-h, 68.43.Fg, 82.33.Pt, 87.15.Aa, 87.15.Kg, 87.19.Xx, 87.19.xj