A computational analysis on boron nitride nanosheet functionalization with 2-thiouracil drug: effects of Al- and Ga‑doping on the adsorption process

In this study, pristine boron nitride nanosheet and those doped with aluminum and gallium (denoted BNNS, BAlNNS, and BGaNNS, respectively) were investigated as potential substrates for the adsorption of the 2-thiouracil (2TU) drug. Intermolecular interactions were characterized using various wavefunction-based methods, including atoms-in-molecules (AIM) and natural bond orbital (NBO) analyses, within the framework of density functional theory (DFT). The results indicate that 2TU undergoes chemical adsorption on all nanosheets. Adsorption is slightly stronger in aqueous solution compared with the gas phase. Consequently, pristine BN nanosheet is a suitable vehicle for 2TU drug delivery, whereas Al- and Ga-doped BN nanosheets can serve as effective adsorbents for removing excess 2TU from environmental systems. The calculated band gap energies (or work functions) for pristine, Al-doped, and Ga-doped BN nanosheets are 6.58 eV (or 3.24 eV), 5.66 eV (or 3.67 eV), and 5.20 eV (or 3.90 eV), respectively. Adsorption of 2TU leads to a notable decrease in band gaps and an increase in work functions for all three nanosheet types, suggesting that they can function as sensors for 2TU, based on changes in electronic conductivity and work function.