Synergistic antibacterial action of lignin-squaraine hybrid photodynamic therapy: advancing towards effective treatment of antibiotic-resistant bacteria.

Antibacterial photodynamic therapy (aPDT) is emerging as an effective means of treating pathogenic bacteria, especially in light of the challenges posed by antibiotic resistance. SQR29, an organophotosensitizer, was encapsulated in a poly(lignin/PEG/PPG urethane) hydrogel to enable targeted treatment at a specific infected area. The hydrogel exhibited free radical scavenging properties which were effective in preventing oxidative stress and promoted wound healing. The hydrogel exhibited a significant aPDT effect on Gram-positive bacteria, hence showing its potential in combating antibiotic-resistant pathogenic bacteria in chronic wound infection.