Freeze-Dried Polysaccharide-Based Tubular Constructs with Enhanced Biofunctionality via Recombinant Polypeptides

Engineering versatile tubular structures is essential for advancing tissue engineering (TE) strategies requiring vascularization. This work proposes the development of 3D tubular constructs based on a synergistic blend of chitosan (CHT), alginate (ALG), and acemannan (ACE). These natural origin materials were selected for their combined benefits including physical stability, antibacterial properties, and the promotion of tissue healing [1-4]. Using freeze-drying technology on the blended solutions, flexible, dimensionally stable tubes featuring well-defined hollow interiors were successfully fabricated. The constructs demonstrated significant water uptake—absorbing approximately 20 times their dry mass—while maintaining structural integrity under physiological conditions over seven days. Morphological characterization by scanning electron microscopy (SEM) and micro-computed tomography (Micro-CT) confirmed the formation of uniform, porous architectures critical for effective nutrient and oxygen diffusion. To enhance bioactivity and mechanical performance, elastin-like recombinamers (ELRs) functionalized with the QK peptide—a vascular endothelial growth factor (VEGF) mimetic sequence—were incorporated into the tubular matrices. Although this modification reduced overall porosity, it preserved a pore size ≥100 µm and promoted an improved microenvironment that supports endothelial cell viability. Moreover, the architecture displayed notable flexibility and bending capability and suitability for suturing, suggesting their potential for dynamic environments where mechanical compliance is crucial and potential for practical surgical applications, where secure attachment and integration with biological tissues are essential.

Furthermore, the sustained release of bioactive components, including ACE and ELRs, up to 7 days contributed to an improved endothelial cell proliferation. These findings demonstrate the potential of this customizable platform for the design of alternative vascular grafts, offering tunable mechanical properties, bioactivity, and dimensions suitable for cardiovascular tissue engineering applications.