Poly(HEMA) hydrogels with controlled pore architecture for tissue regeneration applications.

The technique for fabrication of soft porous hydrogels, in which both the size and the orientation of inner pores can be controlled, was developed. Three-dimensional hydrophilic gels based on poly[2-hydroxyethyl methacrylate] are designed as scaffolds for regeneration of soft tissues, e.g., nerve tissue. Anisotropic macropores of the size ranging from 10 to 50 microm were formed (1) by using a porogen-leaching method with a solid organic porogen, (2) by phase-separation during gelation in solvent-nonsolvent mixture, or (3) by combination of solid porogen elimination and phase-separation. As a porogen, poly(L-lactide) fibers were applied and consequently washed away under mild conditions to obtain desired spatial orientation of pores. Highly water-swollen polymer gels were characterized with high pressure (low vacuum) scanning electron microscopy (AquaSEM). The morphology of voids remaining after removing the solid PLLA porogen (the macropores) was clearly shown.