Self-Defensive Antimicrobial Shape Memory Polyurethanes with Honey-Based Compounds.

Infection treatment plays a crucial role in aiding the body in wound healing. To that end, we developed a library of antimicrobial polymers based on segmented shape memory polyurethanes with nondrug-based antimicrobials (i.e., honey-based phenolic acids (PAs)) using both chemical and physical incorporation approaches. The antimicrobial shape memory polymers (SMPs) have high transition temperatures (>55 °C) to enable maintenance of temporary, programmed shapes in physiological conditions unless a specific external stimulus is present. Polymers showed tunable mechanical and shape memory properties by changing the ratio, chemistry, and incorporation method of PAs. Cytocompatible (∼100% cell viability) synthesized polymers inhibited growth rates of (∼100% with physically incorporated PAs and >80% with chemically incorporated PAs) and (∼100% for samples with cinnamic acid (physical and chemical)). Crystal violet assays showed that all formulations inhibit biofilm formation in surrounding solutions, and chemically incorporated samples showed surface antibiofilm properties with . Molecular dynamics simulations confirm that PAs have higher levels of interactions with cell membranes than . Long-term antimicrobial properties were measured after storage of the sample in aqueous conditions; the polymers retained their antimicrobial properties against after up to 20 days. As a proof of concept, magnetic particles were incorporated into the polymer to trigger user-defined shape recovery by applying an external magnetic field. Shape recovery disrupted preformed biofilms on polymer surfaces. This antimicrobial biomaterial platform could enable user- or environmentally controlled shape change and/or antimicrobial release to enhance infection treatment efforts.