PLA/PCL-based foams as scaffolds for tissue engineering applications

In this paper a novel procedure to produce rigid polymeric foams, with well interconnected open pores and with potential application as scaffolds for tissue engineering, is presented. The materials were prepared starting from a precursor obtained by melt blending a poly(L-lactic acid) (PLLA)/poly(caprolactone) (PCL) blend with a superabsorbent polymer (SAP), consisting of crosslinked particles of sodium polyacrylate. Immersion in water allowed the SAP particles to swell and leach from the matrix, giving rise to a foam structure, easily and safely obtained without the need of organic solvents or chemical foaming agents. The achievement of a proper property profile and foamed structure was investigated through thermal, mechanical and morphological analyses on the prepared systems, comparing properties and structure before and after SAP particles leaching. SEM analysis evidenced the precursor structure formed by a PLLA matrix embedding PCL particles (average diameter: 6 μm) and SAP particles (30-50 μm), and the achievement of a porous structure after water immersion. The effectiveness of the SAP particles leaching was ensured by the weak particles-matrix adhesion, as suggested by mechanical tests. A preliminary biological investigation showed that the chemical composition allowed good cell adhesion on neat and foamed PLA/PCL blends, and highlighted the role of the interconnected porous morphology in significantly increasing cell proliferation.