Additive Manufacturing of Carbon Nanotube Reinforced Bioactive Glass Scaffolds for Bone Tissue Engineering

Abstract

Scaffolds play an essential role in bone healing by providing temporary structural support to the native bone tissue and by hosting bone cells. To this end, several biomaterials and manufacturing methods have been proposed. Among the biomaterials, bio-active glasses have attractive properties as a scaffold material for bone repair. Simultaneously, additive manufacturing (AM) techniques have attracted significant attention owing to their capability of fabricating complex and patient-specific scaffolds. Accordingly, borosilicate bio-active glass (BG-B30) has been used to fabricate the scaffolds using an extrusion-based AM devices in this study. Pluronic F-127 was used as an ink carrier that showed suitable shear thinning behavior for fabrication. The pure BG-B30 scaffold had a compressive strength of 23.30 MPa and was reinforced further with functionalized multiwalled carbon nanotube (MWCNT-COOH) to reduce its brittleness and enhance its compressive strength. When compared to the conventional polymer foam replication technique, the combination of MWCNT-COOH reinforcement and AM resulted in an enhancement of the compressive strength by ∼646% (1.05 MPa to 35.84 MPa). Further, structural analysis using microcomputed tomography revealed that the scaffolds fabricated using AM had better control over strut size and pore size in addition to better network connectivity. Finally, in vitro experiments demonstrated its bio-active behavior by the formation of hydroxyapatite, and the cellular studies revealed good cell viability and osteogenesis initiation. These results are promising for the fabrication of patient-specific CNT-reinforced bio-active glass porous scaffolds for bone tissue engineering applications.