Supercritical carbon dioxide foaming of elastomer/heterocyclic methacrylate blends as scaffolds for tissue engineering

Abstract

This study reports on the supercritical carbon dioxide (scCO₂) foaming of rubber toughened heterocyclic methacrylates for potential applications as non-degradable scaffolds in tissue repair and engineering. Porous blends of styrene–isoprene–styrene copolymer elastomer (SIS) and tetrahydrofurfuryl methacrylate (THFMA) at three SIS/THFMA compositions that ranged from methacrylate to elastomer rich were foamed and characterised in terms of their morphological, mechanical and biological properties. The results showed that the foaming factor (FF) was dependent on blend composition and the foaming conditions demonstrating that the process was tuneable. A greater FF, resulting in higher open and total porosities, was obtained for THFMA rich formulations, which were demonstrated by a predominantly open pore structure. Quasi-static and dynamic mechanical analysis (DMA) showed that the foamed SIS/THFMA blends gave distinct behaviours according to their compositions which were in the range of mechanical properties of soft tissues. The loss modulus and mechanical loss tangent through DMA gave two transition regions associated with the glass transition temperatures of poly(THFMA) and polystyrene components in the blends, along with a reduction in storage modulus. Cell adhesion and spreading in terms of neuroblastoma (human neuron-like SH-SY5Y) cells and ovine meniscal chondrocytes were demonstrated for scaffolds with THFMA rich formulations confirming their suitability for tissue engineering.