Collagen-inducing biologization of prosthetic material for hernia repair: Polypropylene meshes coated with polyP/collagen.

Prostethic mesh material such as nonabsorbable polypropylene used in open and laparoscopic hernia repair are characterized by controllable mechanical properties but may elicit undesirable physiological reactions due to the nonphysiological inert polymer material. We succeeded in developing a biocompatible coating for these meshes, based on a physiological inorganic polymer, polyphosphate (polyP) that is morphogenetically active and used as a metabolic energy source, and a collagen matrix. The polyP/collagen hydrogel material was prepared by a freeze-extraction method, with amorphous Ca-polyP microparticles. Electron microscopy (SEM and REM) studies revealed that the polyP/collagen coats are built up of ≈50 nm-sized microparticles deposited onto the collagen matrix which forms a continuous layer around the polypropylene fibers that also spans the mesh pores. This bioresorbable inorganic/organic hybrid coat was found to be degraded during three days of incubation in medium/serum. The biomechanical properties of the coated meshes are comparable to those of the unmodified polypropylene meshes, with a higher toughness in longitudinal orientation and a more pronounced extensibility in the transverse orientation. The polyP/collagen coating improved cell attachment to the polypropylene meshes and strongly increase the growth of fibroblasts (MC3T3-E1 cells). Furthermore, those mats upregulate the expression of the gene encoding the stromal cell-derived factor-1α (SDF-1), a mesenchymal stem cells attracting chemokine in the fibroblasts. We conclude that coating of inert polymer meshes with a biocompatible, collagen-inducing polyP/collagen inorganic/organic hybrid layer may improve tissue integration of the meshes and the outcome of surgical hernia repair and may redudce the foreign body reaction in contaminated field.