Functionalized 3D-printed scaffolds for enhanced osteogenesis and guided bone regeneration.

In this study, we introduced an innovative approach to guided bone regeneration (GBR) that effectively addresses the challenges of treating large bone defects. Our pioneering 3D-printed multifunctional scaffolds uniquely integrate polycaprolactone (PCL), chitosan (Cs), L-arginine (L-Arg), and β-tricalcium phosphate (β-TCP), leveraging the synergistic effects of these materials to enhance immunomodulation, bioactivity, and mechanical integrity. These PCL/Cs-L-Arg/βTCP scaffolds exhibit remarkable mechanical properties (Young's modulus ∼32.84 ± 4.11 MPa) and maintain structural integrity for 60 days under physiological conditions when fabricated through extrusion-based 3D printing. A key feature of this composite is the dual role of L-Arg, which not only supports osteogenesis but also acts as a potent immunomodulator. The scaffolds facilitate the sustained release of L-arginine over 21 days, fostering a pro-regenerative environment that promotes significant immunomodulatory effects, including a decrease in pro-inflammatory cytokines (IL-6, TNF-α) and an enhancement of anti-inflammatory and osteogenic growth factors (BMP-2, TGF-β) in macrophages. This cytokine profile shift suggests a transition from a pro-inflammatory M1 phenotype to an anti-inflammatory M2 phenotype. A progressive increase in alkaline phosphatase activity, nearly double that of PCL/Cs scaffolds by day 21, reflects enhanced osteogenic differentiation. Additionally, the scaffolds demonstrate exceptional bioactivity, with over 83% and 93% reductions in calcium and phosphorus ions, respectively, in simulated body fluid over 28 days, as evidenced by Alizarin red staining. This integrated approach signifies a major breakthrough in biomaterial design for GBR, presenting transformative potential for treating bone defects in dental and orthopedic applications, and marking a significant leap forward in the field of bone regeneration.