Investigation of the N-Si Dative Bond at the atomistic level in drug carrier/drug delivery nanosensor applications of Si-CNTs

Abstract

This study investigates the interaction of drug molecules with silicon-functionalized carbon nanotubes (Si-CNTs) through N→Si dative bonding, aiming to elucidate their potential in drug delivery and carrier systems. Quantum chemical analysis of N→Si bonds, based on bond length, electron density at bond critical points (ρ_BCP), Laplacian (∇²ρ), and energy density parameters revealed varying bond strengths and characters across different drug–Si-CNT complexes. Most N→Si interactions exhibited weak to moderate dative character, suggesting transient binding suitable for controlled drug release in delivery applications. Notably, one complex of Imiquimod (IMQ)/Si-CNTs structures displayed a strong covalent-like dative bond, indicating its potential as a stable drug carrier. Findings from QTAIM, NCI, and RDG analyses underscore the key role of N→Si dative bonds in governing drug adsorption and release on Si-CNT platforms and demonstrate the usefulness of topological and energetic parameters for predicting drug–nanotube interactions. It may be suitable for both drug delivery and carrier systems. The N→Si coordinative bond is not only a fundamental bonding mode that controls the electronic and chemical properties of Si-CNTs; it is also a decisive theoretical element in targeted drug delivery, nanosensor design, and the rational design of functional carbon nanomaterials