In Vitro Modeling of Tendon with Type I Collagen Scaffolds

In vitro collagen scaffolds provide simplified systems for investigating tendon properties without the use of animal models. However, common scaffold processing approaches, including dehydration and chemical crosslinking, can alter scaffold water content, molecular structure, thermal, and mechanical properties in ways that are not fully understood. In this study, we investigate the influence of ethanol-induced dehydration and genipin crosslinking on type I collagen scaffolds and compare their chemical and thermal properties with native murine Achilles tendons. Fourier Transform Infrared Spectroscopy (FTIR) demonstrated that ethanol treatment reduced molecularly bound water (from 127.3 to 48.0 a.u.) and caused shifts in amide bands (Amide I upshift, Amide II & III downshifts) commonly associated with dehydration, bringing values closer to those of native tendon. Genipin crosslinking further increased similarity to tendon, particularly in thermal behavior as measured by thermogravimetric analysis (TGA). Ten millimolar genipin-treated scaffolds pre-rehydration most closely approximated tendon but diverged post-rehydration. Crosslinking strongly restricted scaffold rehydration (final swelling factor 44.46 vs. 4.06) and altered mechanical properties. Together, these results demonstrate that dehydration and crosslinking influence collagen scaffolds across molecular, thermal, hydration, and mechanical properties. Careful control of these processing conditions, particularly hydration history, is therefore important for collagen-based in vitro models mimicking physicochemical features of native tendon.