Growth Factor‐Loaded Mesoporous Silica Particles, Incorporated in Electrospun PCL Fibres, Provide Topographical and Chemical Cues for Tendon Tissue Engineering

Abstract This study develops a biomaterial‐based strategy to address challenges in controlled growth factor delivery for tenogenic differentiation of mesenchymal stromal cells (MSCs) and tendon stem cells (TSCs). The 20% polycaprolactone (PCL) fibres, electrospun from acetic acid (AA) or formic acid:acetic acid (FA:AA) solutions, are loaded with bovine serum albumin (BSA) to evaluate initial protein‐solvent interactions. SEM characterization demonstrated that fibres from AA has larger diameters (391 ± 0.2 nm) than those from FA:AA (282 ± 0.5 nm), with a further increase in diameter upon BSA incorporation. ATR‐FTIR analysis confirmed successful protein loading but associated structural changes, particularly in AA fibres. Mesoporous silica nanoparticles (MSNs) are then optimized to encapsulate the model biomolecules BSA, lysozyme, and GDF‐7, achieving high encapsulation efficiencies (80–100%) and sustained release due to electrostatic affinity. The MSNs, incorporated into aligned PCL fibres, better protect biomolecule stability and demonstrate uniform distribution, confirmed by SEM‐EDS. Functional cell‐based assays reveal good cell viability and metabolic activity for MSCs and TSCs cultured on the fibres, further enhanced under physoxic conditions (2% O₂). The scaffold, integrating aligned fibres and MSNs, provides a biomimetic 3D structure for controlled cell alignment and tissue formation. This system offers tuneable drug delivery and shows potential as an autograft alternative for tendon regeneration.