Synthetic Mimics of Antimicrobial Peptides (SMAMPs) in Layer-by-Layer Architectures: Possibilities and Limitations

Polymer‐based synthetic mimics of antimicrobial peptides (SMAMPs) show promising antimicrobial activity in solution and as surface‐attached networks. In this paper, their potential as active ingredients in layer‐by‐layer (LbL) assemblies is evaluated. These consist of the weak, anionic polyelectrolyte poly(acrylic acid), and either the hydrophobic butyl SMAMP or the hydrophilic diamine SMAMP (both of which are cationic, weak polyelectrolytes). In situ surface plasmon resonance spectroscopy is used to optimize the LbL assembly conditions. An “overshooting” is observed when depositing the SMAMP layer. Zeta potential measurements show that the layer charge inversion is reduced at each build‐up step due to layer interpenetration. Thus, the positive charge of LbL assemblies with SMAMPs as the top layer is low; a significant part is consumed to maintain layer stability. This leads to reduced antimicrobial activity. Fine‐tuning of the assembly and post‐treatment conditions leads to SMAMP‐PAA LbL systems with optimized antimicrobial activity and stability. Competing Interests: The potential of polymer‐based synthetic mimics of antimicrobial peptides (SMAMPs) as active ingredients in antimicrobial layer‐by‐layer architectures is investigated. These systems are studied by zeta potential measurements, surface plasmon resonance spectroscopy, and antimicrobial assays. The charges of the polycationic SMAMPs are needed both for layer stability and antimicrobial activity. Therefore, the assembly conditions need to be carefully adjusted.