Comparison of polylactic acid/polycaprolactone membrane-coated composite meshes for repairing pelvic floor defects fabricated by two processing methods

Abstract

Applying mesh to reconstruct the pelvic floor is a new surgery method developed in recent years. The composite mesh property is expected to reach perfection by taking advantage of absorbable material and non-absorbable material. This work adopts the dipping method and the electrospinning method to produce polylactic acid/polycaprolactone (weight ratio = 7/3) membrane-coated composite meshes (D-PP1, D-PP2, E-PP1, E-PP2). The effect of coating methods on the mesh structure, such as thickness and weight, is first measured. The electrospinning membrane is tested for only around 3% of the mesh weight, while the dipping membrane is tested for more than 30%. The composite meshes then experience mechanical testing, including tensile strength, bursting strength and flexibility. The coating process is demonstrated to increase elongation at the break in tensile testing: E-PP1 (76.7%) > D-PP1(60%) > PP-1(41.2%); D-PP2 (143.3%) > E-PP2(112.3%) > PP-2(56.7%). It also strengthens the bursting strength: D-PP1 (179.8 N) > E-PP1(157.3 N) > PP-1(149.8 N); D-PP2 (183 N) > E-PP2(174.8 N) > PP-2(154.3 N). However, the dipping method shows weaken composite mesh flexibility, with larger initial modulus for D-PP1 and D-PP2 meshes. Hydrophilicity is represented by the water contact angle and absorption rate. Even though the result of the hydrophobic surface on the composite mesh is reported to easily cause shrinkage, the polypropylene mesh base in this study is considered to prevent this phenomenon. E-PP1 mesh degrades in 20 weeks; D-PP2 mesh degrades in 34 weeks with an induction period of 20 weeks. The optical density value tested, measuring biocompatibility, proves the non-toxicity of both E-PP1 and D-PP2 meshes.