Work

Multiscale porous geopolymer-hydroxyapatite composite scaffolds fabricated via hollow-core bead assembly for bone tissue engineering

Year: 2026

Type: article

Abstract: This work reports the first fabrication of porous geopolymer–hydroxyapatite (GH) scaffolds via a spherical bead-assembly approach. The resulting composite represents a new class of materials that integrate a tailored calcium-phosphate composition of spherical beads with mould-based arrangement process. The shear-thinning rheology of GH mixtures enables precise processing control, while thermogravimetric and thermomechanical analyses (TGA, TMA) define the optimal calcination regime. The assembled scaffolds exhibit hierarchical porosity, with macrostructural domains spanning tens to hundreds of micrometres and interconnected inter-bead voids up to 2 mm (micro-CT and SEM). Moreover, the mesoporous framework is evidenced by a monomodal pore size distribution in the 20–30 nm range, as determined by MIP. The optimized architecture, featuring closed porosity of less than 15 vol% and a densely packed arrangement, exhibited high compressive strength in the range of 16–24 MPa. This favorable microstructural condition is further enhanced by a preferred chemical composition with CaO and P2O5 contents up to 15 wt.% (XRF), leading to the formation of secondary calcium phosphates, namely β-TCP and/or TTCP. In addition, the biological response aligned closely with microstructure and surface topography. A rapid initial adhesion triggered greater LDH release, suggesting membrane stress likely due to HA decomposition products. GH scaffolds demonstrated consistent cellular proliferation with minimal cytotoxicity and stable long-term viability, indicating favorable biocompatibility and optimal scaffold–host interactions. These characteristics position them as a promising novel class of geopolymer-based biomaterials.

Source: Results in Engineering

DOI: 10.1016/j.rineng.2026.110764