A possible method to avoid skin effect in polymeric scaffold produced through thermally induced phase separation

Scaffold's morphology and in particular pore architecture is a key parameter for cell viability and tissue regeneration. Usually, morphology is managed through Thermally Induced Phase Separation (TIPS) consisting of controlled quenching and freeze-drying to remove ice crystals to create porosity. Nevertheless, the so-called skin effect, a less-/non-porous layer, usually occurring at scaffold's air–liquid or material-mold interface. Skin effect reduces scaffold's performance then the layer have to cut out with consequent loss of material and damage risks. Here, it is presented a possible method to avoid skin effect at mold-polymer interface in biopolymer-based scaffolds. It is based on producing scaffolds not directly in a mold but on a previously frozen distilled water surface. SEM analysis showed the absence of skinned surfaces and a uniform pore pattern in shape and size.