WEB Bi-functional drug-laden 3D printed silk fibroin based scaffold for bone tissue engineeringTuesday (22.09.2020) 16:25 - 16:40 B: Biomaterials Part of:
Scaffold mediated tissue engineering has become a golden solution for the regeneration of damaged bone tissues that lack self-regeneration capability. A successful scaffold in bone tissue engineering comprised of a multitude of suitable biological, microarchitectural, and mechanical properties that acting as different signaling cues for the cells to mediate the new tissue formation. Therefore, careful designing of bioactive scaffold macro and microstructures in multiple length scales and biophysical properties fulfilling the tissue repair demands are highly required yet very challenging to achieve. In our study, the attempt is to design an antibacterial and cell responsive three-dimensional (3D) cell-based hybrid scaffolds with exploiting from the novel yet simple chemical processing e.g. sol-gel and self-assembly with a controlled microstructural designing through advanced processing techniques e.g. microextrusion based 3D printing and unidirectional freeze casting approaches . As the main constituent of our biocompatible scaffold of this study, we used the silk fibroin (SF) extracted from B. mori cocoon . However, to increase the cell responsivity and bactericidal efficiency, a thiol ended antibacterial and cell adhesive peptide sequences (SH-AMP-RGD) has been conjugated to the SF polymer through a covalent attachment using a spacer molecule. This followed by processing the AMP-RGD-SF as a 3D printable hydrogel. In the next step, the hybrid hydrogel was successfully printed into the construct with interconnected structure with hierarchically organized porosity and a combination of several useful properties. Namely, due to the covalent linkage of the antibacterial peptide to the SF, the scaffold indicates potent bactericidal efficiency toward gram-positive and negative bacteria. Besides for the sake of osteoconductivity and osteogenicity and mechanical stability, we loaded the hydrogel with inorganic components such as 3D silica nanostructures so that SF and silica could intertwine together through parallel sol-gel and self-assembly processing to support the mechanical structure in the final scaffold. Finally, this study supports the promise of 3D printed SF based hybrid aerogels and hydrogel constructs for repairing the bone defect.
 G. Koons et al. Nature Reviews Materials (2020), 3062.  H. Maleki* et al., ACS Appl. Mater. Interfaces, 2019, 11, 19, 17256–17269.  H. Maleki* et al. Adv. Eng. Mat, 2020, DOI: 10.1002/adem.202000033.