Enhancing the stiffness of electrospun nanofiber scaffolds with a controlled surface coating and mineralization

A new method was developed to coat hydroxyapatite (HAp) onto electrospun poly(lactic-co-glycolic acid) (PLGA) nanofibers for tendon-to-bone insertion site repair applications. Prior to mineralization, chitosan and heparin were covalently immobilized onto the surface of the fibers to accelerate the nucleation of bone-like HAp crystals. Uniform coatings of HAp were obtained by immersing the nanofiber scaffolds into a modified, 10-fold-concentrated simulated body fluid (m10SBF) for different periods of time. The new method resulted in thicker and denser coatings of mineral on the fibers compared to those produced by previously reported methods. Scanning electron microscopy measurements confirmed the formation of nanoscale HAp particles on the fibers. A mechanical property assessment demonstrated a higher stiffness with respect to previous coating methods. A combination of the nanoscale fibrous structure and bonelike mineral coating could mimic the structure, composition, and function of mineralized tissues.