Adjusting degradation rate, mechanical properties and bioactivity of 3D-Printed biphasic calcium phosphate scaffolds by silk fibroin/ platelet-rich plasma lysate coating for regeneration of craniofacial bone defects

Despite many advances, reconstruction of craniofacial bone defects has faced many challenges due to their complex anatomy. For this purpose, in recent decades, researchers have focused on developing biomimetic and patient-specific engineered tissues. In this study, we developed scaffolds designed specifically for craniofacial bone defects, featuring optimal mechanical properties and degradation rates. To this end, porous scaffolds based on Na- and Mg-doped carbonated hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) were prepared using 3D printing. The printed scaffolds were then coated with silk fibroin (SF) and human platelet-rich plasma lysate (HPL). The degradation rate of the scaffolds was optimized in terms of HA to β-TCP ratio, pore size, and layers of the SF coating. Mechanical tests showed that the Young's modulus, compressive strength, and toughness of the scaffolds increased from 0.093 ± 0.006 GPa, 2.939 ± 0.54 MPa and 8.531 ± 1.092 MJ m⁻³ to 0.228 ± 0.029 GPa, 52.521 ± 5.29 MPa and 237.757 ± 18.754 MJ m⁻³ (P < 0.001), respectively by coating with SF. To investigate the regenerative potential of the scaffolds, the behavior of cultured mesenchymal stem cells (MSCs) derived from adipose tissue on the samples was evaluated. The results showed that treatment of scaffolds with HPL promoted cell viability and adhesion and alkaline phosphatase (ALP) activity, which makes biphasic calcium phosphate (BCP)/SF/HPL composite scaffolds promising bone substitutes.