Bioengineered Silicon-Doped Graphdiyne Conjugated with Amino Acid Derivatives for Levodopa Delivery: A DFT-Based Nanoplatform.

This present work focuses on designing and identifying a probable nanocarrier for neurological drug-delivery applications. Silicon-doped graphdiyne (Si-GDY), exhibiting notable modulation in its electronic structure, was functionalized with amino acid derivatives (dopamine, octopamine, and tyramine) to evaluate molecular interactions. A systematic investigation of these nanocarriers was performed by using quantum chemical density functional theory (DFT). To explore the adsorption prospective of pristine and Si-TA-GDY nanocarriers toward the loading of levodopa (L-Dopa), an anti-Parkinson drug, through two different configurations (A and B). The adsorption (-26.811 kcal/mol) energy confirms stable equilibrium of L-Dopa on Si-TA-GDY (B). The lowest deformation energy (0.04892 kcal/mol) reveals minimal lattice strain. Si-TA-GDY@L-Dopa (A) shows energetically favorable adsorption via solvation stabilization (ΔEadsorp,solv) in both water (-27.720 kcal/mol) and ethanol (-23.164 kcal/mol), indicating potential drug-carrier binding affinity. High solvation stabilization energies ΔEsolv in water (-49.462 kcal/mol) and ethanol (-75.905 kcal/mol) demonstrate effective dielectric screening. Additionally, temperature-dependent thermochemical parameter analysis reveals spontaneous and exothermic adsorption dominated by enthalpic stabilization (-25.400 kcal/mol) and shows the highest firmness (ΔG = -13.783 kcal/mol) in Si-TA-GDY@L-Dopa (B). For the same system, the longer recovery time correlates with the higher NEB-derived desorption barrier (∼0.29 eV), enabling controlled drug release. Among all investigated complex structures, Si-doped GDY functionalized with tyramine exhibits the most favorable system toward L-Dopa at both configurations, suggesting that tyramine-functionalized Si-doped GDY serves as a promising candidate for future L-Dopa drug-delivery investigations for neurological disorder.