Nonwoven polycaprolactone scaffolds for tissue engineering: The choice of the structure and the method of cell seeding

Nonwoven polycaprolactone materials produced by electrospinning are perspective internal prosthetic implants. Seeding these implants with multipotent mesenchymal stromal cells stimulates the replacement of the prosthesis with recipient's own connective tissue. Electrospinning method was used for producing polycaprolactone matrices differing in thickness, pore diameter, fiber size, and biomechanical properties. Labeled cells were seeded on scaffolds in three ways: (1) static, (2) dynamic, and (3) directed flow of the cell suspension generated by capillary action. Cell distribution on the surface and the interior of the scaffolds was studied; the metabolic activity of cells was measured by MTT assay. Static seeding method yielded fully confluence of cells covered the entire scaffold surface, but the cells were located primarily in the upper third of the matrix. Dynamic method proved to be effective only for scaffolds of thickness greater than 500 microns, irrespective of the pore diameter. The third method was effective only for scaffolds with the pore diameter of 20-30 microns, regardless of the material thickness. Resorbable nonwoven polycaprolactone electrospun materials have appropriate biomechanical properties and similar to native tissue matrix structures for internal prosthesis. The choice of the most effective cell seeding method depends on the spatial characteristics - the material thickness, pore diameter, and fibers size, which are determined by the electrospinning conditions.