Theoretical investigation on sensing of the epinephrine neurotransmitter by doped C60 fullerenes

Abstract

This study focuses on the adsorption behavior of the epinephrine (EPH) neurotransmitter onto the surface of pristine, B- and Si- doped C<inf>60</inf> fullerenes, using density functional theory (DFT) calculations at the B3LYP/6–31 G(d,p) level of theory. The adsorption performance is analyzed through structural, electronic, and energetic features. Results indicate that EPH physisorbs onto the pristine C<inf>60</inf> with a slight adsorption energy of −1.7 kcal/mol, while the introduction of B- and Si- doping significantly increases the adsorption energies to −14.2 and −37.3 kcal/mol, respectively, when oxygen atom of OH- group of side chain of EPH interacts with C<inf>59</inf>B and C<inf>59</inf>Si fullerenes. This increase may be attributed to a larger number of N-H···π, C-H···π and O-H···π interactions. Epinephrine adsorption onto the surface of fullerenes induces a reduction in the energy gap, which correlates with enhanced electrical conductivity and sensitivity towards EPH. The increased magnitude of the dipole moment in the aqueous phase exhibited by the most favorable nanohybrids of pristine, B-, and Si- atom doped fullerenes results in enhanced solubility, a key parameter for their function in the human body. Based on the electron localization function (ELF) and reduced density gradient (RDG) analyses, significant charge transfer from B- or Si- atoms of the doped fullerene to the oxygen of the EPH is observed, revealing the charge-transfer nature of the nanohybrids. Moreover, Gibbs free energy calculations in both the gas and aqueous phases confirm the spontaneity of EPH adsorption onto the fullerene's surface. Consequently, B- and Si- doped fullerenes are introduced as promising chemical sensors for the EPH neurotransmitter. © 2025 Elsevier B.V.