Coating of 3D-printed poly (ε-caprolactone) scaffolds with silk protein sericin enhances the osteogenic differentiation of human mesenchymal stem cells

Poly (epsilon-caprolactone) (PCL) as a biodegradable polymer is widely employed in scaffold fabrication. Nonetheless, PCL is a hydrophobic polymer and biologically inactive, which is considered a drawback for cell attachment and tissue engineering. Thus, some surface modifications are necessary to enhance its bioactivity. Here, NaOH-treated scaffolds were immersed in (N-morpholino) ethanesulfonic acid solution containing N-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide followed by incubation in sericin solution. Scanning electron microscopy (SEM) results demonstrated 0/90(0) strand orientation and well-defined interconnected pores. The presence of sericin on the treated scaffold was manifested as a light nanoscale roughness compared to the raw PCL scaffold. The average porosity percentage in PCL scaffold equaled 67.9%. The presence of bands at 1538 and 1650 cm(-1) in Fourier-transform infrared (FTIR) spectra of the sericin-coated scaffold was attributed to Amide II and Amide I, indicative of sericin presence on PCL scaffold. The water contact angle in the PCL scaffold was 105(0), where sericin coating combined with NaOH treatment decreased contact angle and increased the hydrophilicity. SEM images, EDX mapping, and X-ray diffraction analysis indicated the presence of calcium and phosphate on sericin-coated scaffolds as a sign of apatite formation. SEM images demonstrated enhanced cell adhesion on sericin-coated scaffold compared to pure PCL, and cells could penetrate interconnected pores. Viability assay proved that sericin did not induce any cytotoxic effect. Also, alkaline phosphatase and calcium deposition assays demonstrated that sericin-coated scaffolds effectively improved osteogenic differentiation of mesenchymal stem cells. Therefore, sericin as a biomaterial is expected to have promising potentials in orthopedic applications.

Automated summary

In this study, the bioactivity of Poly (epsilon-caprolactone) (PCL) scaffold was enhanced through surface modification with sericin. The sericin-coated scaffold exhibited improved hydrophilicity and well-defined interconnected pores, leading to enhanced cell adhesion and penetration. The results of various assays demonstrated the potential of sericin-coated scaffold for orthopedic applications.