Production of Functional Materials Derived from Regenerated Silk Fibroin by Utilizing 3D Printing and Biomimetic Enzyme-induced Mineralization

• Published in: Chinese journal of polymer science Vol. 42; no. 3; pp. 299 - 310
• Main Authors: Chen, Ni, Luo, Fei-Yu, Yang, Gong-Wen, Yao, Jin-Rong, Chen, Xin, Shao, Zheng-Zhong
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 01.03.2024; Springer Nature B.V
• Subjects: Alkaline phosphatase; Aqueous solutions; Biocompatibility; Biomimetic materials; Bone marrow; Bone surgery; Calcium; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Extrusion; Functional materials; Glycerophosphate; Hydrogels; Hydroxyapatite; Hydroxypropyl cellulose; Industrial Chemistry/Chemical Engineering; Mineralization; Orthopedics; Polymer Sciences; Research Article; Silk fibroin; Stem cells; Substitute bone; Three dimensional composites; Three dimensional printing; Biomineralization; Alkaline phosphatase; Extrusion-based printing; Silk protein
• ISSN: 0256-7679; 1439-6203
• DOI: 10.1007/s10118-023-3059-3

Critical-sized bone defects, commonly encountered in clinical orthopedic surgery, present a significant challenge. One of the promising solutions is to prepare synthetic bone substitute materials with precise structural control, mechanical compatibility, and enhanced osteogenic induction performance, nevertheless the successful preparation of such materials remains difficult. In this study, a two-step technique, integrating an extrusion-based printing process with biomimetic mineralization induced by alkaline phosphatase (ALP), was developed. Initially, a pre-cured hydrogel of regenerated silk fibroin (RSF) with a small quantity of hydroxypropyl cellulose (HPC) and ALP was prepared through heating the mixed aqueous solution. This pre-cured hydrogel demonstrated thixotropic property and could be directly extruded into predetermined structures through a 3D-printer. Subsequently, the 3D-printed RSF-based materials with ALP underwent biomimetic in situ mineralization in calcium glycerophosphate (Ca-GP) mineralizing solution, utilizing the polymer chains of RSF as templates and ALP as a trigger for cleaving phosphate bonds of Ca-GP. The resulting 3D-printed RSF-mineral composites including hydrogel and sponge possessed adjustable compression modulus of megapascal grade and variable hydroxyapatite content, which could be controlled by manipulating the duration of the mineralization process. Moreover, these 3D-printed RSF-mineral composites demonstrated non-cytotoxicity towards rat bone marrow mesenchymal stem cells. Therefore, they may hold great potential for applications involving the replacement of tissues characterized by osteoinductivity and intricate structures.