Embroidery-Based Needle Punching as a Novel Strategy to Improve the Performances of Hybrid Textile Medical Implants

Textiles have been widely used as medical implant materials because they combine favorable mechanical properties, unique flexibility, porosity and biocompatibility. These textiles can be tailored for a wide range of clinical applications, including hernia meshes, vascular grafts, stent grafts or heart valves. However, at implantation time, textiles undergo the Foreign Body Reaction (FBR) mechanism, which needs to be controlled in order to ensure the long-term performances of these implants. Actually, the natural porosity and fibrous arrangement of woven textiles in particular, used when stability and strength are required, tend to induce exaggerated tissue ingrowth. This may prevent the implants from remaining flexible, which is particularly critical for hernia meshes or heart valve leaflets. Conversely, non-woven textiles tend to limit FBR but lack strength and stability under cyclic loading. In this study, the rationale is to create a mechanically interlocked hybrid textile combining a woven and a non-woven layer, presenting the hairiness of non-woven on both sides towards FBR limitation, while being as strong as woven. For that purpose, a woven polyethylene terephthalate (PET) fabric layer and a PET spun-bond non-woven layer were assembled using an embroidery-based needle punching process. The influence of the needle-punching stitch density on the physical and mechanical properties of the hybrid textile as well as on its behavior in contact with mesenchymal stem cells (MSCs) was investigated. Results bring out that the assembling process provides strong cohesion between the textile layers. When the stitch density is increased, the fibrous construction becomes more compact, less thick and less stiff with a slight loss in strength. Regarding cell interaction, MSC metabolic activity increased over time for all textile conditions, with the hybrid textiles exhibiting an intermediate response between the woven and non-woven textiles. These findings bring out that embroidery-based needle punching provides an effective approach for manufacturing strong and flexible hybrid textiles expected to limit exaggerated FBR when used as implant.