Photodynamic, UV-curable and fibre-forming polyvinyl alcohol derivative with broad processability and staining-free antibacterial capability
Journal:
arXiv
Published Date:
Feb 3, 2025
Abstract
Antimicrobial photodynamic therapy (APDT) is a promising antibiotic-free
strategy for broad-spectrum infection control in chronic wounds, minimising
bacterial resistance risks. However, rapid photosensitiser diffusion, tissue
staining, side toxicity, and short-lived antimicrobial effects present
significant clinical limitations for integrating APDT into wound dressings. To
address these challenges, we present the design of a bespoke polyvinyl alcohol
(PVA) derivative conjugated with both phenothiazine and methacrylate
functionalities, enabling staining-free antibacterial photodynamic effects,
cellular tolerability and processability into various wound dressing formats,
including films, textile fibres and nanoscale coatings. Tosylation of PVA is
leveraged for the covalent coupling of toluidine blue, as confirmed by UV-Vis
spectroscopy and the minimal release of TB in vitro. UV-induced network
formation is exploited to accomplish cast films and nanoscale integrated wound
dressing coatings. UV curing is also successfully coupled with an in-house wet
spinning process to realise individual, water-insoluble fibres as the building
blocks of fibrous wound dressings. A fluorometric assay supports the generation
of reactive oxygen species when the UV-cured samples are exposed to work, but
not UV, light, yielding a mean log10 reduction of up to 2.13 in S. aureus, and
the complete eradication of P. aeruginosa. Direct and extract cytotoxicity
tests with UV-cured films and fibres demonstrate the viability of L929
fibroblasts following 60-min light irradiation and 72-hour cell culture. The
bespoke molecular architecture, broad processability and cellular tolerability
of this PVA derivative are highly attractive aiming to integrate durable
staining-free photodynamic capability in a wide range of healthcare
technologies, from chronic wound dressings up to minimally invasive localised
therapy.
