Fabrication and properties of superparamagnetic Fe3O4-graft-poly(L-glutamic acid) porous scaffolds via solution casting and particulate leaching

A novel magnetic nanocomposite was successfully synthesized by grafting Poly(L-glutamic acid) (PLGA) onto Fe3O4 nanoparticles, achieved through the carboxylation of a Fe3O4-graft-poly(γ-benzyl-L-glutamate) (Fe3O4-g-PBLG) precursor with trimethyliodosilane. The chemical structure of the resulting Fe3O4-graft-Poly(L-glutamic acid) (Fe3O4-g-PLGA) was unequivocally confirmed by 1H NMR and FT-IR spectroscopy. This composite exhibited superparamagnetic behavior (saturation magnetization: 6.73 emu/g) and enhanced hydrophilicity (contact angle: 36.6°). Porous scaffolds were fabricated via a well-established solution casting and particulate leaching technique using NaCl as a porogen. By precisely controlling the porogen amount (10 g and 15 g per gram of composite), scaffolds with tailorable macroporous architecture were obtained, featuring pore sizes of 250 ± 30.98 μm and 450 ± 39.72 µm, and interconnected porosities of 90.2 ± 2.95% and 96.9 ± 3.67%, respectively. A comprehensive evaluation of the scaffolds’ physical properties revealed high water retention capacities (1179 ± 73.26% and 1051 ± 69.35%), tunable compressive moduli (0.35 ± 0.05 MPa and 0.21 ± 0.02 MPa), and viscoelastic storage moduli ranging from 5500 to 6500 Pa. In vitro degradation studies in PBS over 20 wk demonstrated controllable biodegradation, with mass losses of 58.22 ± 2.36% and 68.69 ± 2.77%, correlating with the scaffold porosity. Finally, preliminary cytocompatibility assessment using adipose-derived stem cells indicated favorable cell adhesion on the scaffold surface, as observed by SEM and LCSM. The tailorable porosity, robust mechanical properties, and superparamagnetic nature of the Fe3O4-g-PLGA scaffolds render them a versatile functional material with broad potential in the field of polymeric biomaterials. However, its comprehensive biological evaluation, including direct cytotoxicity tests and in vivo performance assessment, is an important direction for future research.