An asymmetric Janus PCL/chitosan bilayer membrane harmonizing mechanical integrity and Osteo-immunomodulatory bioactivity for periodontal regeneration

This study introduces a new bioactive Janus membrane for guided bone regeneration (GBR) to treat periodontal bone defects. • Unlike conventional barrier membranes that lack long-term stability or biological function, our bilayer membrane, composed of poly(ε-caprolactone) (PCL), chitosan (CS), and the natural polyphenol proanthocyanidin (PA), combines mechanical strength with antioxidant, antibacterial, and anti-inflammatory properties. • Its asymmetric design, with in situ biomineralized hydroxyapatite particles (HAp) on a chitosan layer, supports bone growth on one side while preventing bacterial invasion on the PA-incorporated side. • This innovative approach addresses major challenges in periodontal tissue engineering and offers a promising platform for more effective and biologically intelligent therapies in clinical bone regeneration. The achievement of periodontal bone regeneration using a barrier membrane in guided bone regeneration (GBR) technology is often limited by either its inferior mechanical strength or bioactivity. To address this limitation, we developed a novel Janus bi-layer membrane by sequentially electrospinning poly(ε-caprolactone) (PCL) mixed with proanthocyanidin (PCL-PA) and chitosan (CS) in acetic acid, then biomineralized it in simulated body fluid (BSF) to form hydroxyapatite particles (HAp) in situ on a CS nanofiber layer (CS-HAp): PCL-PA/CS-HAp. This bi-layer membrane exhibited superior mechanical performance compared to single-layer membranes, with a peeling strength of 58 J/m 2 and tensile strength exceeding 5.0 MPa under hydrated conditions. In vitro antioxidant assays demonstrated the strong free-radical-scavenging ability of PCL-PA/CS-HAp. In addition, the PA-incorporated membranes exhibited greater than 95% bacterial inhibition against both Gram-negative E. coli and Gram-positive S. aureus . The bilayer membrane also alleviated oxidative stress induced by hydrogen peroxide (H 2 O 2 ), thereby promoting the proliferation of MC3T3-E1 cells, as monitored by cytoskeletal staining. Flow cytometry analysis showed that the PA-incorporated membrane can stabilize immunomodulatory effects by about 10% in lipopolysaccharides (LPS)-stimulated RAW264.7 cells. When used in a rat periodontal bone defect model, significant bone regeneration was observed in the PCL-PA/CS-HAp group, with a bone volume to total volume ratio of 36.2% and a significant reduction in bone defect size after 8 weeks, outperforming other treatment groups ( p  < 0.001). The PCL-PA/CS-HAp bi-layer membrane represents a promising strategy for guided bone regeneration, effectively combining mechanical stability and bioactive properties. A bi-layer barrier membrane, PCL-PA/CS-HAp, prepared via electrospinning, was effective for periodontal bone regeneration in a rat model. Download: Download high-res image (192KB) Download: Download full-size image