Gene therapy, which treats genetic diseases by fixing defective genes, has gained significant attention. Viral vectors show great potential for gene delivery but face limitations like low transduction efficiency and poor targeting. Loading viral vectors onto tissue engineered scaffolds presents a promising strategy to address these challenges, but their widespread application remains limited by challenges like vector stability, biomaterial selection, and high manufacturing costs. Adeno-associated virus (AAV), recognized for its safety, high efficiency, and low immunogenicity, was employed as a model virus. In this study, AAV was encapsulated within electrospun fibers (AAV/PCL-PEO@Co-ES) composed of polycaprolactone (PCL) and polyethylene oxide (PEO) via coaxial electrospinning, ensuring effective AAV protection and controlled release. The physicochemical characterization results indicated that the scaffold exhibited excellent mechanical properties (tensile strength: 3.22 ± 0.48 MPa) and wettability (WCA: 67.90 ± 8.45°). In vitro release and cell transduction assays demonstrated that the AAV-loaded scaffold effectively control viral vector release and transduction. Furthermore, the in vitro cell and in vivo animal experiments suggested that the AAV-loaded scaffolds exhibit excellent biocompatibility and efficient viral vector delivery capability. Hence, our research not only enhances the storage and delivery of viral vectors but also provides innovative solutions for viral vector delivery strategies.

Three dimensional printable formulation of self-standing and vascular-supportive structures using multi-materials suitable for organ engineering is of great importance and highly challengeable, but, it could advance the 3D printing scenario from printable shape to functional unit of human body. In this study, the authors report a 3D printable formulation of such self-standing and vascular-supportive structures using an in-house formulated multi-material combination of albumen/alginate/gelatin (A-SA-Gel)-based hydrogel. The rheological properties and relaxation behavior of hydrogels were analyzed prior to the printing process. The suitability of the hydrogel in 3D printing of various customizable and self-standing structures, including a human ear model, was examined by extrusion-based 3D printing. The structural, mechanical, and physicochemical properties of the printed scaffolds were studied systematically. Results supported the 3D printability of the formulated hydrogel with self-standing structures, which are customizable to a specific need. In vitro cell experiment showed that the formulated hydrogel has excellent biocompatibility and vascular supportive behavior with the extent of endothelial sprout formation when tested with human umbilical vein endothelial cells. In conclusion, the present study demonstrated the suitability of the extrusion-based 3D printing technique for manufacturing complex shapes and structures using multi-materials with high fidelity, which have great potential in organ engineering.