Electrospun poly(3-hydroxybutyrate) fibers containing pheophorbide derivatives: Structural, photophysical, and...

The study explores novel electrospun poly(3-hydroxybutyrate) (PHB) systems for pheophorbide derivative (PheoD) photosensitizers delivery in anticancer photodynamic therapy (PDT). The photophysical properties of PheoD within PHB matrix and the resulting impact on polymer morphology (SEM, AFM), supramolecular structure (XRD, EPR), mechanical behavior, in vitro release, cytotoxicity assay on A431 cells, and antimicrobial properties were investigated. It was shown, that the difference in the PheoD's radical does not affect PHB's semicrystalline nature and amorphous region's structure but causes significant changes in the morphological characteristics of the surface. Notably, mC₄ and mC₂N + increased tensile strength from 0.9 MPa to 1.2 and 3.1 MPa respectively due to the morphological changes. It was found, that the incorporation of 0.03 % of PheoD into PHB matrixes leads to regulated release rate of PheoD, reduced toxicity, and enhanced antibacterial efficiency. So, the cumulative release up to 35 % was found for PHB-mC₂NH₂ which correlated with the highest antimicrobial activity against Gram+ and Gram- bacteria and the highest light-inducted toxicity and a delayed release up to 30 % for PHB-mC₂N + in accordance to 2-10 % less antimicrobial activity and 5 % lower light-inducted toxicity. The proposed systems demonstrated the best balance of properties, as well as 80 % and 40 % higher efficiency in PDT in the PHB-PheoD system compared to pure PheoDs.