Dynamic Compression Accelerates Degradation-Coupled Mechanical Deterioration of Biomimetic Scaffolds: An In Vitro Platform Study

Conventional static immersion tests do not reproduce the repetitive mechanical loading experienced by scaffolds implanted in load-bearing tissues. In this study, an in vitro cyclic compression platform was developed to evaluate incubation-associated mass loss and mechanical deterioration under controlled loading conditions. Three representative scaffold systems were investigated, including a physically crosslinked polyvinyl alcohol (PVA) hydrogel, a PVA hydrogel reinforced with 2% cellulose nanocrystals (PVA + 2% CNC), and a three-dimensionally printed silk fibroin/collagen (SF/Col) scaffold. Samples were incubated in lysozyme-containing phosphate-buffered saline under either static immersion or cyclic compression. The device exhibited stable and reproducible loading behavior during operation. The results showed that dynamic loading enabled clearer discrimination of time-dependent mechanical deterioration than static observation alone. The three scaffold systems exhibited distinct mass-retention, stress-relaxation, and structural-stability responses over time. After 3 weeks, the mass loss of the SF/Col scaffold increased from 26.4% under static conditions to 41.8% under dynamic compression. In contrast, the PVA-based hydrogels showed better resistance to structural failure, and the PVA + 2% CNC hydrogel exhibited the best retention of compressive and viscoelastic properties under experimental conditions. These differences reflect scaffold-system-dependent behaviors that arise from the combined effects of composition, porous architecture, processing route, stabilization treatment, and degradation-induced structural evolution, rather than from intrinsic material chemistry alone. Overall, this study demonstrates that dynamic cyclic compression provides a useful platform for assessing degradation-related mechanical functionality of porous scaffolds. The method may serve as a practical in vitro screening tool for comparing scaffold-system performance under mechanically relevant conditions, although further studies are needed before extrapolating these findings to in vivo behavior.