Plant cellulose-based biomimetic artificial Small-Diameter vascular materials enabled by gradient Dual-Network entanglement

The development of materials that can act as small-diameter artificial blood vessels (SDABV) and can withstand the dynamic mechanical pressures and strains of native blood vessels (NBV) still represents a major challenge in cardiovascular disease treatment. Here, we report a biomimetic approach inspired by the hierarchical structure and interconnectivity of NBV that enables the fabrication of cellulose-based SDABV (2–5 mm). The ABV materials have an interconnected dual-network structure with a stiff regenerative cellulose hydrogel as the matrix and a photo-polymerized poly(hydroxyethyl methacrylate) as the filler. The distribution of the poly(hydroxyethyl methacrylate) in the cellulose network displays a gradient pattern. This produces a composite gel tube material that has a hierarchical structure with a dense and smooth surface, as well as a loose porous interior, which closely resembles that of NBV. As a result, the cellulose based SDABV shows similar mechanical performance with their natural counterparts, including tensile strength (1.4 MPa), strain (93 %), Young's modulus (2.98 MPa) and toughness (1040KJ/m3). Moreover, the materials show excellent suture retention and burst pressure that are sufficient to meet the requirements for ABV transplantation. In vitro biocompatibility experiments showed that the composite gel materials have excellent cell compatibility, blood compatibility, and low fibrinogen adsorption and platelet adhesion that is conducive to inhibiting thrombosis. In vivo experiments on rabbit models have shown that implanting the materials for three months does not cause blood vessel blockages or inflammatory responses. Overall, the bionic-structured and functional dual-network hydrogel grafts demonstrate tremendous potential in the application of SDABV. The knowledge gained in this study will help future design and application of novel high-performance cellulose-based SDABVs.