Antibacterial Activity of Various Morphologies of Films Based on Guanidine Derivatives of Pillar[5]arene: Influence of the Nature of One Substitute on Self-assembly

The progress of the pillar[5]­arene chemistry allowed us to set out a new concept on application of the supramolecular assemblies to create antimicrobial films with variable surface morphologies and biological activities. Antibacterial films were derived from the substituted pillar[5]­arenes containing nine pharmacophoric guanidine fragments and one thioalkyl substituent. Changing the only thioalkyl fragment in the macrocycle structure made it possible to control the biological activity of the resulting antibacterial coating. Pretreatment of the surface with aqueous solution of the amphiphilic pillar[5]­arenes reduced the biofilm thickness by 56 ± 10% of Gram-positive Staphylococcus aureus in the case of the pillar[5]­arene containing a thiooctyl fragment and by 52 ± 7% for the biofilm of Gram-negative Klebsiella pneumoniae in the case of pillar[5]­arene containing a thiooctadecyl fragment. Meanwhile, the cytotoxicity of the synthesized macrocycles was examined at a concentration of 50 μg/mL, which was significantly lower than that of bis-guanidine-based antimicrobial preparations.