Fabrication of water-stable soy protein isolate (SPI)/ carboxymethyl cellulose (CMC) scaffold sourced from oil palm empty fruit bunch (OPEFB) for bone tissue engineering

Abstract

Low structural integrity in hydrophilic polymers poses a significant challenge for bone tissue engineering (BTE) as these scaffolds are prone to premature collapse, potentially impeding bone regeneration. Additionally, there is a scarcity of research on sustainable approaches in bone scaffold fabrication, warranting further exploration given their biocompatibility. This study addresses these issues by fabricating water-stable, glutaraldehyde (GA) crosslinked soy protein isolate (SPI)/carboxymethyl cellulose (CMC) porous scaffolds using oil palm empty fruit bunch (OPEFB) waste as the starting material. The scaffolds were prepared through blending, crosslinking, and freeze-drying processes, followed by several characterisation experiments to assess morphology, porosity, mechanical properties, and degradation rate. The results showed that the SPI/CMC scaffolds exhibited a rough surface morphology with an average pore size ranging from 65 ± 13 μm to 99 ± 8 μm. The porosity of the SPI/CMC-based scaffolds was higher than that of the SPI-based scaffolds, though the increased porosity led to a lower Young’s modulus. A decrease in Young’s modulus was observed with increasing CMC content, attributed to the inefficiency of SPI-GA crosslinking. The scaffolds demonstrated a slow degradation profile over 35 days of incubation in simulated body fluid (SBF), indicating their potential to retain structural integrity over extended periods. Additionally, a fluctuating weight change due to calcium phosphate deposition suggested the bioactive properties of the scaffolds. In vitro studies revealed that these waste-derived scaffolds supported and maintained cellular proliferation of human fetal osteoblast (hFOB) cells, with good cell attachment observed, highlighting their potential for BTE applications. This study demonstrates that the SPI/CMC scaffold with GA crosslinking effectively provides structural stability in aqueous environments and can be further improved as one of the potential candidates for the BTE scaffold.