Low-dose STS–PEG–chitosan coating on PLCL scaffolds: A multifunctional strategy for endothelialization, anti-inflammation, and antithrombosis in vascular grafts

The long-term success of small-diameter vascular grafts remains limited by thrombosis, chronic inflammation, and poor endothelialization. To address these challenges, we developed a multifunctional coating strategy by integrating polyethylene glycol–chitosan (PEG–CS) with low-dose sodium tanshinone IIA sulfonate (STS, 0.01 %) on poly(L-lactide-co-ε-caprolactone) (PLCL) scaffolds. The PEG–CS/STS coating significantly improved hydrophilicity and structural stability, while providing bioactivity that promoted endothelial cell proliferation and alignment. In vitro studies demonstrated markedly reduced platelet adhesion and activation, along with a favorable shift in macrophage polarization toward the anti-inflammatory M2 phenotype. These synergistic effects create a vascular-friendly microenvironment that promotes endothelialization and suppresses thrombosis and inflammation. PEG reduces platelet adsorption, allowing STS to exert its anti-inflammatory effects, while chitosan’s electrostatic interaction with STS supports its stable loading and controlled release, enhancing its bioactivity. Our findings highlight that the PEG-CS/STS modified scaffold effectively integrates endothelialization, immunomodulation, and antithrombotic protection, representing a promising next generation strategy for small diameter vascular grafts.