Egg albumin enhances kappa (κ)-carrageenan hydrogels for tunable physicochemical, mechanical, and biological performance

Hydrogels are versatile polymeric materials valued for their crosslinked structures, which mimic the extracellular matrix. Their tunable size, shape, and pore architecture make them attractive for diverse biomedical applications. In this study, we developed a novel biohybrid hydrogel composed of κ-carrageenan and egg albumin. Egg albumin, extracted from fresh egg whites (Gallus gallus domesticus), was quantified using the Bradford assay. Protein molecular masses were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and confirmed via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Hydrogel scaffolds were fabricated through ionotropic gelation, forming an interpenetrating polymer network of κ-carrageenan and egg albumin, with sodium chloride (NaCl) and potassium chloride (KCl) from phosphate-buffered saline (PBS) serving as crosslinking agents. Fourier-transform infrared spectroscopy (FTIR) was used to assess polymer crosslinking, and scaffold stability was evaluated through swelling behavior, degradation rate, and mechanical strength. Surface morphology analysis revealed a dense, folded network in pure κ-carrageenan hydrogels, whereas egg albumin incorporation yielded smoother surfaces with protein aggregates-features that increase surface heterogeneity and may promote cell adhesion. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays with NIH 3T3 (mouse embryonic fibroblast) cells demonstrated significantly higher cell proliferation on egg albumin-blended hydrogels compared with pure κ-carrageenan on days 1, 4, and 7. These results indicate that egg albumin-copolymerized hydrogels are promising candidates for soft tissue engineering and drug delivery applications.