Tunable microporous PLA architectures designed via stearic acid as a multifunctional porogen

Despite advances in bone tissue engineering (BTE), challenges remain due to the limited availability of materials that meet processing requirements, provide structural stability, and offer tunable physicochemical properties. Polylactic acid (PLA)-stearic acid (SA) blends, obtained via melt compounding, are hereby presented as a strategy to enhance the tunability of microporous materials for BTE applications. SA, a biocompatible saturated fatty acid, was incorporated into PLA, where it acts as a porogen, modulating rheology, crystallization behavior, and pore formation. The porogen was then removed by supercritical CO2 (scCO2) leaching. PLA-SA blends were systematically investigated in terms of thermal, rheological, and morphological properties. Rheological analyses showed that SA significantly reduces viscosity and relaxation times. Differential scanning calorimetry and ATR-FTIR spectroscopy revealed partial miscibility between PLA and SA, with SA acting as a crystallization agent. AFM phase-contrast analysis also confirmed that, at low SA fractions, the two polymers are miscible. Homogeneous microporous structures were obtained via selective SA scCO2 leaching. The leaching further induced PLA crystallization in the thermodynamically stable α phase. Scanning electron microscopy coupled with image analysis showed that pore density increases with the initial SA content, while pore size remains narrowly distributed in the micrometer range. N2 adsorption test revealed that a mesoporous, interconnected structure forms upon leaching. The proposed approach allows the production of structurally stable, porous PLA architectures with enhanced surface areas suitable for advanced functional and biomedical applications.