Description
Polyhydroxyalkanoates (PHAs) represent a premier class of bio-based polyesters with significant potential as eco-friendly alternatives to traditional plastics; however, their inherent hydrophobicity often limits their processability and biological applications. This research proposes a sustainable chemical modification strategy to overcome these limitations through a novel amidation process employing the biocompatible ionic liquid choline taurinate ([Ch][Tau]) to introduce sulphonic moieties on the polyester backbone. This green chemistry approach enables precise control over the degree of functionalization and the resulting amphiphilic properties. The obtained structures, composed of hydrophobic (polyester) and hydrophilic (taurine) units, showed the ability to self-assemble in an aqueous environment and encapsulate usnic acid, a powerful antimicrobial agent. A key innovation of this work lies in the comprehensive evaluation of the antimicrobial performance of modified PHAs, both alone and in the presence of usnic acid. The antimicrobial characterisation was conducted through a dual-stage experimental setup comparing static and dynamic conditions. While traditional static assays provided a baseline for antibacterial efficacy, the core of our characterization utilized advanced microfluidic platforms to simulate physiologically relevant environments. By implementing dynamic microfluidic testing, we were able to monitor bacterial behaviour and material-pathogen interactions under continuous flow and controlled shear stress. This microfluidic approach proved essential to demonstrate that the [Ch][Tau]-modified PHAs maintain superior antimicrobial activity and anti-fouling properties even under hydrodynamic regimes, which are not capturable via standard static methods. These findings highlight the potential of functionalized PHAs as versatile biomaterials for high-performance applications, such as wound healing and advanced drug delivery systems, where performance under flow is a critical requirement. This study underscores how the synergy between sustainable macromolecular engineering and microfluidic characterisation can unlock the full potential of next-generation biopolymers.