3D-Printed composite scaffolds coated with collagen and tetracycline for enhanced bone regeneration and antibacterial activity

Bones play a crucial role in the human body by providing mechanical support, enabling movement, and protecting vital organs. Although bone is a vascularized tissue capable of self-regeneration, large defects, severe trauma, or conditions such as infections or metabolic disorders, often require surgical intervention. Treatments typically involve autografts, allografts, or xenografts, each presenting limitations like donor site morbidity, limited availability, immune rejection, and the risk of disease transmission [ 1 ]. Tissue engineering presents a promising solution. Advances in 3D bioprinting and biomaterials allow the development of bone scaffolds specifically designed for regeneration. These structures can also serve as drug delivery systems (DDS) by incorporating therapeutic agents, such as antimicrobial or anti-inflammatory compounds, directly into the scaffold. The inclusion of antimicrobials is particularly important to minimize the risk of infection during and after implantation [ 2 ]. In this study, 3D-printed composite scaffolds were coated with a collagen type I solution containing the broad-spectrum antibiotic tetracycline hydrochloride (TCH). The scaffolds consisted of poly(ε-caprolactone) (PCL) and β-tricalcium phosphate (β-TCP) at a 70:30 w/w ratio and were fabricated using the BIO X Bioprinter (Cellink, Sweden). Collagen type I was reconstituted in 0.02 M acetic acid at 500 μg/mL. A 0.25 M TCH stock solution was diluted to final concentrations of 2.5, 5, and 10 mM. Scaffolds were immersed in these solutions, incubated at 37°C with 5% CO 2 for 2 hours, and airdried for 6 hours. The drug-loaded scaffolds demonstrated antibacterial activity against Staphylococcus aureus and satisfactory biocompatibility, supporting their potential in bone tissue engineering applications. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany