Exploring the drug delivery capabilities of Nb₂C MXene functionalized with oxygen and fluorine: A DFT study

MXenes quantum dots (QDs), including Nb₂C, Nb₂CO₂, and Nb₂CF₂, are emerging materials with exceptional structural, electronic, and optical properties, making them highly suitable for biomedical applications. This study investigates the structural optimization, stability, electronic properties, and drug-loading potential of these QDs using fluorouracil (Flu) as a model drug. Structural analyses show that the functionalization of Nb₂C with O and F atoms enhances stability, with binding energies (BEs) of 7.335, 8.154, and 6.704 eV for Nb₂C, Nb₂CO₂, and Nb₂CF₂, respectively. The drug-loading study reveals that Nb₂C exhibits the highest adsorption energy of -6.775 eV at the surface site (2.053 Å), while Nb₂CO₂ and Nb₂CF₂ demonstrate weaker interactions with adsorption energies of -2.163 eV and -0.933 eV, respectively. Non-covalent interaction (NCI) and natural bond orbital (NBO) analyses show significant changes in electron density distribution upon drug interaction, with the natural charge on the O7 atom in Flu shifting slightly upon interaction. Optical property investigations indicate a blue shift in the absorption spectra for Nb₂CO₂ (λ_max = 764.76 nm) and Nb₂CF₂ (λ_max = 1108.71 nm), compared to Nb₂C (λ_max = 2612.00 nm), confirming the tunability of these materials for therapeutic applications. By addressing key challenges in drug delivery, such as stability, controlled release, and interaction strength, this study establishes Nb₂CO₂ and Nb₂CF₂ as promising nanocarriers, with the potential to improve drug efficacy and minimize side effects in targeted cancer therapies.