Vascular regeneration and patency maintenance, without anticoagulant administration, represent key developmental trends to enhance small-diameter vascular grafts (SDVG) performance. In vivo engineered autologous biotubes have emerged as SDVG candidates with pro-regenerative properties. However, mechanical failure coupled with thrombus formation hinder translational prospects of biotubes as SDVGs. Previously fabricated poly(ε-caprolactone) skeleton-reinforced biotubes (PBs) circumvented mechanical issues and achieved vascular regeneration, but orally administered anticoagulants were required. Here, highly efficient and biocompatible functional modifications were introduced to living cells on PB lumens. The 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine-N-methoxy (DMPE)-PEG-conjugated anti-coagulant bivalirudin (DPB) and DMPE-PEG-conjugated endothelial progenitor cell (EPC)-binding TPS-peptide (DPT) modifications possessed functionality conducive to promoting vascular graft patency. Co-modification of DPB and DPT swiftly attained luminal saturation without influencing cell viability. DPB repellent of non-specific proteins, DPB inhibition of thrombus formation, and DPB protection against functional masking of DPT\'s EPC-capture by blood components, which promoted patency and rapid endothelialization in rat and canine artery implantation models without anticoagulant administration. This strategy offers a safe, facile, and fast technical approach to convey additional functionalization to living cells within tissue-engineered constructs.

The aim of this study was to explore and evaluate biotubes consisting of autologous tissues. The biotubes were prepared by intra-abdominally embedding silicon rods as moulds. The specimens were analyzed by mechanical tests, histological observation and superficial study. The intra-abdominal implantation of the silicone tubes readily stimulated the development of the biotubes. The biotubes consisted of collagen-rich extracellular matrices. Myofibroblasts appeared as elongated cells with circumferential or longitudinal orientations. Subsequent to one month of embedding, the thickness of the tube wall was 70-250 μm. The burst strength was 1100±187 mmHg and the suturability was excellent. Biotubes that have the ability to be widely variable in their shapes are composed of autologous cells and glomerular extracellular matrices. Biotubes are ideal grafts for tissue engineering as they are able to avoid immunological rejection and are of sufficient mechanical strength.