Fabrication of self-assembled peptidomimetic microspheres and hydrogen peroxide responsive release of nicotinamide

The self-assembly of peptidomimetic compounds containing urea and dipicolinic acid was studied to develop a targeted drug delivery vehicle using hydrogen peroxide as a stimulus. Peptidomimetic compound 1 capped with N,N′-dicyclohexylurea mimicked a peptide turn structure, while compound 2 adopted a rigid planar structure through intramolecular N-H⋯O and N-H⋯N hydrogen bonding interactions. The AFM and FE-SEM images revealed that peptidomimetic compound 1 formed microspheres, whereas compound 2 formed a tape-like structure. These microspheres were loaded with the anticancer drug nicotinamide. The microspheres disassembled in the presence of hydrogen peroxide. Hydrogen peroxide ruptured the microspheres composed of peptidomimetic compound 1, thereby enhancing the proportional release of the loaded drug molecules. The reported peptidomimetic microspheres hold future prospects for use as targeted drug delivery vehicles for cancer cells with high levels of H₂O₂.