Hydrolytic Degradability, Cell Tolerance and On-Demand Antibacterial Effect of Electrospun Photodynamically Active Fibres

TL;DR

This study develops electrospun photodynamically active fibres with controlled microstructure, demonstrating their potential for on-demand antibacterial action and supporting cell growth, suitable for infection control and wound healing.

Contribution

It introduces a novel fabrication of semicrystalline electrospun fibres with tunable properties for enhanced antibacterial and biocompatible performance under physiological conditions.

Findings

Fibres with crystalline domains show long-lasting microstructure and controlled drug release.

PAFs effectively promote cell attachment and proliferation.

They achieve significant bacterial reduction upon light activation.

Abstract

Photodynamically active fibres (PAFs) are a novel class of stimulus-sensitive systems capable of triggering antibiotic-free antibacterial effect on-demand when exposed to light. Despite their relevance in infection control, however, the broad clinical applicability of PAFs has not yet been fully realised due to the limited control in fibrous microstructure, cell tolerance and antibacterial activity in the physiologic environment. We addressed this challenge by creating semicrystalline electrospun fibres with varying content of poly[(L-lactide)-co-(glycolide)] (PLGA), poly(epsilon-caprolactone) (PCL) and methylene blue (MB), whereby the effect of polymer morphology, fibre composition and photosensitiser (PS) uptake on wet state fibre behaviour and functions was studied. The presence of crystalline domains and PS-polymer secondary interactions proved key to accomplishing long-lasting fibrous microstructure, controlled mass loss and controlled MB release profiles (37 degC, pH 7.4, 8 weeks). PAFs with equivalent PLGA:PCL weight ratio successfully promoted attachment and proliferation of L929 cells over a 7-day culture with and without light activation, while triggering up to 2.5 and 4 log reduction in E. coli and S. mutans viability, respectively. These results support the therapeutic applicability of PAFs for frequently encountered bacterial infections, opening up new opportunities in photodynamic fibrous systems with integrated wound healing and infection control capabilities.