Preparation and characterisation of controlled porosity alginate hydrogels made via a simultaneous micelle templating and internal gelation process

Controlled porosity alginate hydrogel monoliths were synthesised by simultaneous micelle templating (MT) and an internal gelation reaction. In water, the self assembling surfactant, cetyltrimethylammonium bromide (CTAB) formed non-spherical micelles that were used as a template for pore formation. The porous microstructure was assessed by mercury intrusion porosimetry (MIP), helium pycnometry, X-ray microtomography (XMT) and scanning electron microscopy (SEM), respectively. The MT hydrogels displayed relatively monodisperse pore size distributions (with pore sizes ranging from 32.5 μm to 164.0 μm), high total pore volumes (4.5–20.3 cm3/g) and high degrees of porosity (83–97%). Some control over pore size distributions was achieved by varying the surfactant concentration; higher surfactant concentrations, led to smaller pores with lower total pore volumes. Uniaxial compression testing revealed that hydrogels made via MT are stable in cell culture media for 28 days. Fourier transform infrared (FTIR) spectroscopy data, suggested that all surfactant could be removed from the final product by washing with ethanol and water, making these hydrogels potentially suitable for tissue engineering (TE) applications.