Bioinspired Suction-Cup Architecture Modulates Hydration and Pomegranate-Extract Release from NVP/HEMA/CMC Hydrogels

Surface architecture may tune hydrogel transport without changing formulation. Flat and suction-cup N-vinylpyrrolidone/2-hydroxyethyl methacrylate/carboxymethyl cellulose (NVP/HEMA/CMC) hydrogels prepared from the same nominal formulation were compared for hydration, equilibrium water content, pomegranate-extract uptake, and 60 min release. Suction-cup hydrogels showed greater short-term swelling (38.7 ± 0.7%) than flat hydrogels (31.4 ± 0.6%), a 23.1% increase, while equilibrium water contents remained similar. Apparent extract uptake, estimated from loading-solution depletion, was 20.45 and 15.74 mg/g hydrated hydrogel for suction-cup and flat formats, respectively. After 60 min, cumulative apparent pomegranate-extract-equivalent release was 6.976 ± 0.681 and 4.208 ± 0.354 mg, respectively, representing a 65.8% increase. These values corresponded to approximately 17.6% and 15.2% of estimated initial loadings. Indirect-extract testing showed minimum viabilities of 86.24% for HaCaT cells and 71.01% for human dermal fibroblasts, exceeding the 70% ISO 10993-5 criterion. Overall, suction-cup architecture increased early swelling, estimated uptake, and cumulative release without altering formulation. Although the individual contributions of surface area, local thickness, liquid retention, and diffusion paths could not be separated, the results demonstrate that architectural modification can enhance early hydration and extract uptake and release while preserving the hydrogel formulation.