Modeling of pristine, Ir- and Au-decorated C₆₀fullerenes as sensors for detection of hydroxyurea and nitrosourea drugs

Even though Hydroxyurea (HU) and Nitrosourea (NU) are well known drugs efficient for chemotherapy, the drugs' misuse and/or release of trace levels of un-metabolized drugs into the environment leads to diverse side effects. Herein, we investigated the potential applications of pristine, Au-, Ir-decorated C60 fullerenes in HU and NU drugs detection using Density Functional Theory (DFT) approach. Based on our results, the adsorption energies were in the range of HU/C60 < NU/C60 < NU/AuC59 < NU/IrC59 and HU/IrC59 corresponding to the calculated energies of - 5.674, - 12.767, - 27.065, - 31.423 and - 31.676 kcal/mol, respectively. The result indicates that Au- and Ir-decorated fullerenes have stronger interactions with the HU and NU drugs when compared with the pristine C60. Furthermore, the energy band gap (Eg) decreases from 4.49 eV (C60) to 4.45 (HU/C60) and 4.47 (NU/C60) eV indicates that HU and NU adsorption has insignificant effect on the electrical conductivity of pristine C60. On the other hand, Ir-metal decoration improved both the reactivity and electronic sensitivity of C60 towards the HU and NU drugs. The topology analysis analyses revealed that the studied complexes are stabilized by covalent bonding and/or weak van der Waals (vdW) forces, with HU/C60 having the least stability. The recovery time (τ) for the desorption of the NU drug from AuC59 fullerene surface was found to be 0.67 s while τ for HU and NU drugs desorption was 54.15 and 69.93 s, respectively, for the IrC59 fullerene surface. Though the AuC59 fullerene may not be an effective electronic sensor, it can be used as work-function based sensor for NU drug detection. Conversely, IrC59 fullerene may potentially be used as both electronic and work-function type sensor for HU and NU drugs detection.