Preparation, structural characterization, and potential applications of diatomaceous earth biomineralized with inorganic calcium and edible polysaccharide composite hydrogels.

Algal polysaccharides are a key source of materials in food, cosmetics, and medical devices due to their excellent bioactivity. The Ulva pertusa polysaccharide was extracted from U. pertusa via hot-water extraction, and the diatomaceous earth was doped with inorganic calcium through a biosynthesis technique. To expand the application of algal polysaccharides, a novel Ca-DE/UPP composite hydrogel was developed by incorporating biomineralized diatomaceous earth (DE) into algal polysaccharide (UPP). The structure of the composite gel was characterized using rheology, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). A gelation mechanism was proposed based on these characterization data. Additionally, the hydrogel exhibited high mechanical strength (G' = 233 Pa), as well as impressive water retention (88.4 %) and water absorption (5.2 g/g). The Ca-DE/UPP composite hydrogel exhibits good cell compatibility and anti-inflammatory properties. Finally, in vitro, scratch assays demonstrated significant enhancement in cell migration, with a migration rate of up to 99.48 % after 48 h. These results suggest the hydrogel's potential as an effective wound dressing for promoting tissue regeneration.