Phenothiazine dye-loaded chitosan cryogels as multifunctional antibacterial wound dressings

Cryogels, owing to their low density, high porosity, lightweight structure, and interconnected three-dimensional network, have gained significant attention for biomedical applications. In the present study, a chalcone-based phenothiazine dye derivative (PTZ-chalcone) was successfully synthesized via direct condensation of 2-acetyl-5-bromothiophene with phenothiazine carboxaldehyde derivatives (Ib) using the Kröhnke method in methanolic KOH. The chemical structure of the synthesized compound was confirmed by spectral analysis. The PTZ-chalcone derivative was subsequently incorporated into chitosan (CS) cryogel matrix to fabricate sponge-like biomaterials. The resulting PTZ-chalcone-loaded CS cryogels were systematically characterized and evaluated, with particular emphasis on their antibacterial properties and their potential use as a wound dressing matrix. Likewise, the PTZ-chalcone-loaded CS cryogels displayed strong antibacterial action. In particular, the bactericidal effects of cryogels (CSC2 and CSC3) were demonstrated against Escherichia coli (33.5 ± 0.1 mm), Pseudomonas aeruginosa (32.4 ± 0.28 mm), Acinetobacter baumannii (31.2 ± 0.41 mm), Staphylococcus aureus (29.2 ± 0.28 mm), Streptococcus pyogenes (28.7 ± 0.35 mm), and Enterococcus faecalis (27.5 ± 0.81 mm). The strong antibacterial activity of the PTZ-chalcone compound was validated by bacterial growth curves and protein leakage assays, demonstrating its ability to disrupt bacterial cell membranes. In the Microtox^® assay, the cryogels exhibited superior thermal stability and biocompatibility with no harmful effects. Further, the molecular docking analysis showed that PTZ-chalcone has a high binding affinity for proteins ((CDK6 and CDK2), suggesting potential applications in combating bacterial infections and cancer. These results imply that chalcone-loaded CS cryogels are efficient multifunctional biomaterials with great potential for woundhealing applications.