Tunable drug delivery via functionalized C18 nanorings: a DFT-MD investigation of 5-fluorouracil adsorption and release

Abstract

Nanomaterials have transformed the field of targeted drug delivery by providing exceptional surface-to-volume ratios, tunable electronic characteristics, and the potential for controlled release mechanisms. They can enhance treatment efficiency, reduce adverse effects, and increase bioavailability by precisely interacting with therapeutic molecules. This investigation investigates the electronic properties and adsorption behavior of 5-fluorouracil (FU) on pristine and doped C₁₈ nanorings (B–C₁₈, N–C₁₈, and Si–C₁₈) using density functional theory (DFT) considering these advantages. Stable and thermodynamically advantageous physisorption is confirmed by the calculated adsorption energies (E_ads) of FU@B–C₁₈ and FU@N–C₁₈, which range from −0.772 eV to −0.930 eV. The band structure is effectively customized by doping, as evidenced by the narrowest band gap (0.463 eV) in FU@Si–C₁₈ compared to 1.861 eV in FU@C₁₈. This suggests that the electronic sensitivity has been enhanced. The Mulliken charge transfer (CT) analysis suggests that FU functions as an electron donor, with the highest charge transfer observed for FU@B–C₁₈ (−0.060e). FU@B–C₁₈ exhibits rapid desorption (9.3 s), while FU@N–C₁₈ exhibits robust retention (4.2 × 10³ s), indicating a balance between release efficiency and stability. Recovery time (τ) varies accordingly. The thermodynamic stability and structural integrity of the FU–C₁₈ complexes are further confirmed by complementary molecular dynamics (MD) simulations, which guarantee dependable performance under physiological conditions. The potential of doped and functionalized C₁₈ nanorings as advanced nanocarriers for FU cancer therapy is underscored by these findings.