Beeswax-enriched tricalcium phosphate/hydroxyapatite/sodium alginate/thymol 3D-printed scaffolds for application in bone tissue engineering

Tissue engineering, particularly bone tissue engineering (BTE), continues to pose significant challenges to modern medicine. In this work, a rapid prototyping technique was explored to create 3D scaffolds using a Fab@Home 3D-Plotter extruder. For that purpose, a novel composite mixture containing tricalcium phosphate (TCP), hydroxyapatite (HAp), sodium alginate (SA), beeswax (BW), and thymol (TM) was formulated. BW and TM resulted in 3D scaffolds with rougher surfaces and moderate hydrophilic profiles, properties crucial for mediating cell adhesion and proliferation. Moreover, the 3D scaffolds containing BW displayed a significant increase in compressive strength and Young modulus, being comparable to those exhibited by trabecular bone. TM loading prevented the establishment of Staphylococcus aureus and Escherichia coli infections, inhibiting bacterial adhesion and proliferation at the scaffolds' surface. Additionally, the cytocompatibility of the scaffolds was confirmed over 21 days, with the adhesion and proliferation of Human osteoblasts (hOB) at the scaffold's surfaces. Simultaneously, calcium and phosphate ions accumulated at the scaffolds' surface, forming apatite crystals. Therefore, this improved composite mixture showed promising results for being applied in BTE, not only facilitating hOB cell adhesion and proliferation but also avoiding bacterial infection, addressing a critical challenge in implant-based therapies.