Foaming + Impregnation One-Step Process Using Supercritical CO₂

Abstract

Polymers are widely used in everyday life due to their properties as toughness, viscoelasticity, and the possibility to form glasses and semicrystalline structures. For that reason, it is used in mostly drug delivery systems and tissue engineering and in pharmaceutical and biomedical investigations. Foaming process allows creating porous structure into the polymer leading to scaffolds. Scaffolds are the focus of many investigations as prolonged drug delivery systems and implants or injections which are used to deliver cells, drugs, and genes into the body. Particulate leaching, freeze-drying, thermally induced phase separation, rapid prototyping, powder compaction, sol-gel, and melt molding are the main techniques in front of supercritical fluid technology to prepare scaffolds. Supercritical foaming process using CO 2 presents advantages as a high dissolution in polymers and a green process because CO 2 is nontoxic, inexpensive, and reusable. Moreover, supercritical technology allows to do an impregnation with an active substance together with the foaming at the same time. Thus active substances entrapped into scaffolds could be fabricated in a one-step green process.