Co-loading of doxorubicin and anti-cancer peptide LL-37 on covalently functionalized carbon nanotubes; a molecular dynamics simulation study

•Development of advanced molecular modeling for drug delivery systems.•Investigations on functionalization of CNT (carbon nanotube) as drug carrier.•Co-loading of doxorubicin (DOX) and LL-37 on covalently functionalized CNTs.•Hydroxyl-functionalized CNT is a suitable carrier in the ratio of 1:1 (DOX: LL-37) An investigation of covalently functionalized carbon nanotubes (f-CNTs) loaded with doxorubicin (DOX) and LL-37 was performed using molecular dynamics simulations. With carboxyl, hydroxyl, and amine groups covalently attached, f-CNTs were functionalized. Adsorption of DOX molecules and LL-37 was investigated in two molar proportions. Binding energy, radial distribution function, and conformational changes of the peptide were investigated. In order to choose a suitable carrier, the structural properties of LL-37 adsorbed on f-CNTs were compared with the aqueous medium. The obtained results demonstrated that hydroxyl-functionalized CNT is a suitable carrier in the ratio of 1:1 (DOX: LL-37), and also amine-functionalized CNT is a suitable carrier in the ratio of 2:1 (DOX: LL-37), which has kept the structure of the peptide stable. Dual drug delivery systems can benefit from these results.