Pelvic organ prolapse (POP) is a common condition among women, characterized by the descent of pelvic organs through the vaginal canal. Although traditional synthetic meshes are widely utilized, they are associated with complications such as erosion, infection, and tissue rejection. This study explores the design and fabrication of biodegradable auxetic implants using polycaprolactone and melt electrowriting technology, with the goal of developing implants that closely replicate the mechanical behavior of vaginal tissue while minimizing implant-related complications. Four distinct auxetic mesh geometries—re-entrant Evans, Lozenge grid, square grid, and three-star honeycomb—were fabricated with a 160 $\mathrm{\mu }$m diameter and mechanically evaluated through uniaxial tensile testing. The results indicate that the square grid and three-star honeycomb geometries exhibit hyperelastic-like behavior, closely mimicking the stress–strain response of vaginal tissue. The re-entrant Evans geometry has been observed to exhibit excessive stiffness for applications related to POP, primarily due to material overlap. This geometry demonstrates stiffness that is approximately five times greater than that of the square grid or the three-star honeycomb configurations, which contributes to an increase in local rigidity. The unique auxetic properties of these structures prevent the bundling effect observed in synthetic meshes, promoting improved load distribution and minimizing the risk of tissue compression. Additionally, increasing the extrusion diameter has been identified as a promising strategy for further refining the biomechanical properties of these meshes. These findings lay a solid foundation for the development of next-generation biodegradable implants.

Pelvic organ prolapse (POP) is a prevalent condition, affecting women all over the world, and is commonly treated through surgical interventions that present limitations such as recurrence or complications associated with synthetic meshes. In this study, biodegradable poly($ϵ$-caprolactone) (PCL) cog threads are proposed as a minimally invasive alternative for vaginal wall reinforcement. A custom cutting tool was developed to fabricate threads with varying barb angles (90°, 75°, 60°, and 45°), which were produced via Melt Electrowriting. Their mechanical behavior was assessed through uniaxial tensile tests and validated using finite element simulations. The results showed that barb orientation had minimal influence on tensile performance. In simulations of anterior vaginal wall deformation under cough pressure, all cog thread configurations significantly reduced displacement in the damaged tissue model, achieving values comparable to or even lower than those of healthy tissue. A ball burst simulation using an anatomically accurate model further demonstrated a 13% increase in reaction force with cog thread reinforcement. Despite fabrication limitations, this study supports the biomechanical potential of 3D-printed PCL cog threads for POP treatment, and lays the groundwork for future in vivo validation.

Pelvic organ prolapse (POP) is a health condition that can significantly impact patients’ quality of life. Unfortunately, most available treatments present drawbacks such as high recurrence rates, risk of complications, poor tissue integration, and the need for reintervention. One promising alternative is the use of biodegradable implantable meshes, which can support the organs, guide tissue regeneration, and be fully absorbed without damaging the surrounding tissues. In this study, biodegradable polycaprolactone (PCL) meshes were fabricated using melt electrowritten (MEW), incorporating the antistatic agent Hostastat^® FA 38 (HT) to address these limitations. The goal was to produce microscaffolds with suitable biophysical properties, particularly more stable fiber deposition and reduced fiber diameter. Different HT concentrations (0.03, 0.06, and 0.1 wt%) were investigated to assess their influence on the fiber diameter and mechanical properties of the PCL meshes. Increasing HT concentration significantly reduced fiber diameter by 14–17%, 39–45%, and 65–66%, depending on mesh geometry (square or sinusoidal). At 0.06 wt%, PCL/HT meshes showed a 24.10% increase in tensile strength and a 55.59% increase in Young’s Modulus compared to pure PCL meshes of similar diameter. All formulations demonstrated cell viability >90%. Differential scanning calorimetry (DSC) revealed preserved thermal stability and changes in crystallinity with HT addition. These findings indicate that the antistatic agent yields promising results, enabling the production of thinner, more stable fibers with higher tensile strength and Young’s Modulus than PCL meshes, without adding cellular toxicity. Developing a thinner and more stable mesh that mimics vaginal tissue mechanics could offer an innovative solution for POP repair.

Additive manufacturing (AM) offers new opportunities for biomedical device design; however, its translation to soft-tissue reinforcement remains challenging, particularly in pelvic organ prolapse (POP) applications requiring mechanical performance and tissue compatibility. In this study, a hybrid AM approach combining melt electrowriting (MEW) and controlled post-processing was developed to fabricate biodegradable poly(ε-caprolactone) (PCL) cog threads for minimally invasive pelvic reinforcement. This integrated fabrication workflow enables the precise deposition of microscale fibers via MEW followed by localized mechanical modification, offering a versatile platform for tailoring graft architecture and anchoring geometry. Smooth filaments were first produced via MEW and subsequently post-processed to introduce barbs for mechanical anchorage. The resulting structures were mechanically characterized through uniaxial tensile testing and evaluated as reinforcement elements in ex vivo sow vaginal tissue using ball burst testing. The MEW-fabricated cog threads increased the ultimate load of vaginal tissue from 83 ± 20 N (control) to 126 ± 15 N, corresponding to a 51.8% improvement (p = 0.0477). Compared with commercial PCL cog threads reported in the literature (177.0 ± 5.4 N), the reinforced specimens achieved approximately 71% of the benchmark load. Owing to their intermediate stiffness profile, the MEW-fabricated cog threads reduced mechanical mismatch with soft tissue compared to high-stiffness commercial alternatives. These findings demonstrate the feasibility of hybrid MEW-based additive manufacturing strategies for engineering mechanically compatible, application-driven soft-tissue reinforcement systems.

Apical prolapse, a common form of Pelvic Organ Prolapse (POP), is often linked to weakened support structures such as the uterosacral (USL) and cardinal ligaments (CL), influenced by factors like vaginal childbirth, aging, and obesity. Although surgical mesh use is expected to increase, the Food and Drug Administration (FDA) banned polypropylene mesh for transvaginal anterior compartment prolapse in 2019 due to safety concerns, highlighting the need for alternatives such as biodegradable implants. This study developed four biodegradable mesh implants (square and sinusoidal geometries) mimicking the USL and CL. These were applied within a computational pelvic model to assess biomechanical behavior during the Valsalva maneuver and to explore different fixation methods (continuous, interrupted and simple stitch sutures). Baseline analysis of the healthy model established vaginal displacement under normal conditions. Without implant support, complete CL rupture increased displacement by 34%, and complete USL rupture raised displacement by 69%. Polycaprolactone implants consistently reduced anterior vaginal wall displacement in all impairment scenarios. Square implants mimicking the USL reduced displacement by up to 10% in cases of complete USL rupture with intact CL. Similarly, square implants mimicking the CL reduced displacement by up to 15% with complete CL rupture and healthy USL. Simulations with both ligaments impaired showed that USL contribute to support, while CL play a key role in stabilization. These findings demonstrate the potential of biodegradable implants to enhance POP repair. However, further studies are needed to evaluate long-term degradation and clinical applicability.