Renewable porous sponge-like polyurethane scaffolds with bioglass: physicochemical, morphological, mechanical, and in vitro biocompatibility properties

ABSTRACT Sponge-like polyurethane has garnered attention in tissue engineering as scaffolds for bone and cartilage repair. This study investigated the incorporation of 45S5 Bioglass (BG) as a reactive filler in a renewable polyurethane sponge-like scaffold synthesized from castor oil-based polyol and the prepolymer using an in situ foaming method. Scaffolds containing 5, 10, and 20 wt.% BG were compared with pristine castor oil-based polyurethane (pristine PU) scaffolds to assess their physicochemical, morphological, mechanical, and in vitro hemolytic and cytotoxicity properties. Results revealed an increase in urethane bond intensity with BG incorporation, enhancing the crosslinking density of the PU matrix. PU/BG scaffolds exhibited a reduction in pore size as BG content increased, with X-ray microtomography confirming a decrease in total porosity. However, scaffolds with higher density (PU/5%, PU/10%, and PU/20%) showed lower compressive strength. In vitro biological assays demonstrated that both PU/BG and pristine PU scaffolds exhibited favorable hemocompatibility and L929 cytocompatibility, with no adverse effects from BG addition. Nevertheless, live/dead staining revealed the presence of live human mesenchymal stem cells (hMSCs) distributed on PU, PU/BG5%, PU/BG10% scaffolds. The fluorescence microscopic image demonstrated a favorable spreading, proliferation and viability of the live cells on these scaffolds. In conclusion, the synthetic route, leveraging renewable precursors, effectively produces PU/BG sponge-like scaffolds with promising applications tissue engineering.