Degradation mechanisms of polyglycolide fibers in knitted fabrics

Alignment degradation kinetics of textile implants with tissue healing timelines is critical to mitigate risks from insufficient mechanical retention. This study investigates the structural and mechanical evolution of polyglycolide (PGA) fibers in a knitted interlock fabric during 28-day in vitro degradation, addressing the challenge of rapid PGA degradation that risks premature mechanical failure in biomedical implants. By integrating wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), and mechanical testing, we systematically evaluate how knitted architecture modulates crystallinity, lamellar structure evolution, tensile strength, and mass loss of the PGA fabric. The results indicate that the interlock stitch significantly delays degradation of PGA fibers, retaining 68% of crystallinity and losing only 14.6% of mass after 28 days of in vitro degradation. However, tensile strength sharply declined by 82% within 14 days, driven by hydrolysis-induced flaws in amorphous regions. The degradation process follows three distinct phases: surface erosion (0–7 days), internal amorphous hydrolysis (7–14 days), and gradual crystalline breakdown (14–28 days), governed by heterogeneous solution accessibility and structural constraints of the knitted loops. These findings reveal that textile-based PGA implants have different degradation behavior from PGA fibers, resulting from yarn twisting, intermeshing loops, and localized stress distribution. This work demonstrates that structural design, rather than fiber-level data alone, dictates the balance between mechanical retention and fast degradation in PGA textile implants. The findings provide actionable strategies to optimize surgical implants through tailored textile engineering, ensuring sustained functionality during tissue regeneration while minimizing biocompatibility risks.