Calcium phosphate coated Keratin–PCL scaffolds for potential bone tissue regeneration

• Calcium phosphate (CaP) was surface coated onto electrospun Keratin–PCL scaffold.
• Homogeneous CaP coating was achieved within 10 min.
• Crosslinked keratin provided nucleation sites for Ca2 + and for CaP deposition.
• Scaffolds showed improved mechanical strength and cell–matrix interactions.

The incorporation of hydroxyapatite (HA) nanoparticles within or on the surface of electrospun polymeric scaffolds is a popular approach for bone tissue engineering. However, the fabrication of osteoconductive composite scaffolds via benign processing conditions still remains a major challenge to date. In this work, a new method was developed to achieve a uniform coating of calcium phosphate (CaP) onto electrospun keratin–polycaprolactone composites (Keratin–PCL). Keratin within PCL was crosslinked to decrease its solubility, before coating of CaP. A homogeneous coating was achieved within a short time frame (~ 10 min) by immersing the scaffolds into Ca2 + and (PO4)3 − solutions separately. Results showed that the incorporation of keratin into PCL scaffolds not only provided nucleation sites for Ca2 + adsorption and subsequent homogeneous CaP surface deposition, but also facilitated cell–matrix interactions. An improvement in the mechanical strength of the resultant composite scaffold, as compared to other conventional coating methods, was also observed. This approach of developing a biocompatible bone tissue engineering scaffold would be adopted for further in vitro osteogenic differentiation studies in the future.