Tunable Mechanical and Biological Performance of Electrospun PLLA Scaffolds via Mesoporous Silica Incorporation and Fiber Architecture Changes

Abstract Electrospun scaffolds with tunable mechanical and biological properties are critical for tissue engineering, where materials must match specific cellular environments. We fabricated poly(l-lactide) (PLLA) fibrous scaffolds incorporating 5 wt % SBA-15 mesoporous silica, controlling fiber morphology through solvent selection and humidity during electrospinning. Four variants were produced: smooth and porous fibers, each with and without silica. Porous fibers, generated via coaxial electrospinning at 70% humidity, reduced silica agglomerate size by approximately half compared to smooth fibers. Mechanical testing showed silica reinforcement strongly enhanced smooth fiber performance: elongation at failure increased 2.6-fold (from 101% to 259%) and toughness doubled (from 2.2 to 5.2 MJ·m−3), while tensile strength remained ∼3 MPa. Porous scaffolds exhibited lower strength (0.1−0.5 MPa), consistent with the porous fiber structure observed in SEM cross-sections. The metabolic activity of MG-63 osteoblasts increased on all scaffolds over seven days. Smooth scaffolds, especially with silica, promoted higher metabolic activity and better cell spreading, whereas porous scaffolds induced localized cell colonies. These findings demonstrate that combining mesoporous silica with fiber architecture control enables tunable mechanical and biological properties. Smooth silica-containing scaffolds demonstrate mechanical performance comparable to commercial guided bone regeneration membranes, while porous variants offer a compliant architecture of potential interest for cranial bone defect repair. In future work, the mesoporous silica could additionally be exploited for local drug delivery.