Complexation‐Induced Resolution Enhancement Pleiotropic Small Diameter Vascular Constructs with Superior Antibacterial and Angiogenesis Properties

3D printing has been widely applied for preparing artificial blood vessels, which will bring innovation to cardiovascular disorder intervention. However, the printing resolution and anti-infection properties of small-diameter vessels (Φ < 6 mm) have been challenging in 3D printing. The primary objective of this research is to design a novel coaxial 3D-printing postprocessing method for preparing small-size blood vessels with improved antibacterial and angiogenesis properties. The coaxial printing resolution can be more conveniently improved. Negatively charged polyvinyl alcohol (PVA) and alginate (Alg) interpenetrating networks artificial vessels are immersed in positively charged chitosan (CTS) solution. Rapid dimensional shrinkage takes place on its outer surface through electrostatic interactions. The maximum shrinkage size of wall thickness can reach 61.2%. The vessels demonstrate strong antibacterial properties against Escherichia coli (98.8 ± 0.5%) and Staphylococcus aureus (97.6 ± 1.4%). In rat dorsal skin grafting experiments, Cu2+ can promote angiogenesis by regulating hypoxia-inducible factor-1 pathway. No artificial blood vessel blockage occurs after 5 days of blood circulation in vitro.