Molecular docking and antibacterial activity of a one-pot synthesized novel polyaniline substituted imidazole (PANI–imidazole) copolymer†

Abstract

The present research deals with the one-pot synthesis of co-doped polyaniline (PANI), and polyaniline–imidazole copolymer by a chemical oxidative polymerization method (COPM). In a typical experiment, aniline and imidazole were mixed in an aqueous acidic solution containing nitric acid (HNO₃) as a dopant and oxalic acid (C₂H₂O₄) as a co-dopant. In the next step, we added ammonium persulfate ((NH₄)₂S₂O₈) as an oxidant. Understanding the structure and properties of polymeric materials requires several techniques, including FTIR, XRD, SEM, TGA, etc. The molecular weight and thermal stability of all the synthesized polyanilines were analyzed by GPC and TGA, respectively. The conductivity measurements of the synthesized PANI and PANI–imidazole copolymers were analyzed by the two probe method. Furthermore, the antibacterial activity of the PANI–imidazole was tested against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) and measured in terms of IC₅₀, minimum bactericidal concentration (MBC), and minimum inhibitory concentration (MIC). Bonding interactions of the imidazole ring with the active amino acid residues of the bacterial enzyme peptide deformylase were investigated by molecular docking. These results suggest that the polyaniline–imidazole copolymer increased the binding affinity towards the bacterial enzyme and showed significant antibacterial activity.