Synergistic bone regeneration by surface-modified 3D-printed PCL/β-TCP scaffolds in various animal defect models

Abstract

The regeneration of large-segmental bone defects remains a significant clinical challenge due to their complex microenvironments. Three-dimensional (3D)-printed polycaprolactone (PCL) scaffolds offer a potential solution but exhibit limited osteoinductive capacity. In this study, 3D-printed PCL/β-tricalcium phosphate (TCP) composite scaffolds were pretreated with NaOH, followed by functionalization with bioactive collagen and β‑TCP. These modifications markedly improved the scaffolds’ hydrophilicity without compromising mechanical integrity. In vitro studies with MC3T3-E1 cells demonstrated that the CS@TCP scaffolds significantly enhanced early osteogenic differentiation compared to C, CS, and CS@COL scaffolds, as indicated by the alkaline phosphatase activity assay. In vivo evaluation using three different rabbit cranial defect models revealed superior new bone formation in the partial-thickness cranial defect (PTD) groups compared to the full-thickness cranial defect (FTD) and intact cranial bone onlay (Onlay) groups, potentially due to the increased vascularization and abundant endogenous stem cells in the PTD groups. Despite reduced new bone formation in the Onlay group, its bone integration advantages may be advantageous for cosmetic surgery applications. This study investigated how β‑TCP surface modification interacts with clinical application-specific microenvironments to maximize the regenerative potential of 3D-printed scaffolds, providing crucial guidance for scaffold design in effective bone defect repair across various clinical scenarios.

 

Keywords

3D-printed scaffolds / In vitro proliferation and differentiation / Multiple animal defect models / Surface modification

Funding

The study was funded by the Natural Science Foundation of Jiangsu Province (BK20210117).

Conflict of Interest

Yulin Jiang, Guanghui Xi, Chen Zhou, Xi Yang, and Dongxu Ke are employees of Novaprint Therapeutics Suzhou Co., Ltd during this study but had no involvement in activities posing a conflict of interest. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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