Immobilized arginine/tryptophan-rich cyclic dodecapeptide on reduced graphene oxide anchored with manganese dioxide for microbial biofilm eradication

To avoid the accumulation of bacterial biofilms in water pipelines, it is critical to develop potent antimicrobial agents with good ability to reduce extracellular polymeric substances (EPS). In this study, cyclic dodecapeptides were synthesized, and different mutations for increasing the ratio of arginine (Arg) and tryptophan (Trp) were introduced. Separately, the synthesized dodecapeptides were immobilized on a reduced graphene oxide nanocomposite anchored with a hierarchical β-MnO 2 (RGO/β-MnO 2 ) hybrid. With a minimum inhibitory concentration of 0.97 g/mL, the immobilized Arg–Trp rich antimicrobial peptides (AMP) on RGO/MnO 2 nanocomposite, Cdp-4/RGO/MnO 2, showed superior efficacy against multidrug-resistant Pseudomonas aeruginosa ATCC 15692 ( P. aeruginosa ) planktonic cells. The immobilized Cdp-4/RGO/β-MnO 2 also eradicated the mature biofilm by 99% with a minimum inhibitory concentration value of 62.5 µg/mL with significant reduction of EPS. These characteristics allow the use of the immobilized Arg–Trp rich AMP as a promising antimicrobial agent against microbial biofilms, present in water distribution systems.