PC@PAM/CaAlg/CaCO3 composite hydrogel films fabricated via surface mineralization and their swelling, phycocyanin release, antibacterial and antioxidant performances

Hydrogel materials capable of loading and releasing functional proteins have attracted extensive attention. In this study, phycocyanin-loaded polyacrylamide/calcium alginate/calcium carbonate (PC@PAM/CaAlg/CaCO 3 ) composite hydrogel films were fabricated by combining a PAM/CaAlg polymer network with in-situ CaCO 3 mineralization. This mineralization strategy provided an additional structural approach for regulating film swelling and PC transport. The effects of the acrylamide/sodium alginate (AM/NaAlg) mass ratio and Na 2 CO 3 concentration on swelling and PC release in phosphate-buffered saline (PBS, pH 7.4) were investigated. The AM/NaAlg ratio of 4:1 resulted in relatively high swelling and PC release, whereas the PC diffusion was substantially restricted at 12:1. The film prepared at 8:1 and treated with 0.20 wt.% Na 2 CO 3 exhibited relatively high swelling and gradual, sustained PC release. This film showed antibacterial inhibition rates of 67.27% against S. aureus and 52.45% against E. coli , while ABTS and DPPH radical-scavenging efficiencies reached 98.29% and 79.68%, respectively.