Fabrication of cryogel polyelectrolyte complex of Tragacanth gum and chitosan with potential biological applications

To provide more insight into the potential applications of the biocompatible polyelectrolyte complexes (PECs) of Tragacanth gum (TG) and chitosan (CS) in the biological fields, the PEC cryogel of TG and CS were fabricated. Different TG:CS ratios were examined to optimize the PEC characteristics. Based on coacervation yield, water absorption, supernatant viscosity, turbidity, and rheological properties, 18:2 was chosen as the optimized ratio of TG:CS. The pH = 4 was selected as the optimized point, resulting in the highest level of interactions between anionic and cationic polysaccharides. The zeta potential of PECs was indicative of the charge neutralization between polyanions and polycations which were also studied by FTIR spectra. The cryogel exhibited a macroporous plate structure in leaf-like form and narrowed mesopores distributed around 2.4 and 4.6 nm. PECs exhibited anti-bacterial activities, reducing 95 % of E. coli within 1 h and 99.9 % after 24 h, as well as 80 % of S. aureus after 1 h and 99.9 % after 24 h. TG:CS cryogel adhered to the human fibroblast cell lines (HFFF2) without cytotoxicity effects. The scratch assay validated that the cryogel effectively induced wound closure in human fibroblast cells within 48 h.