3D Bioprinting of Cardiovascular Tissues for In Vivo and In Vitro Applications Using Hybrid Hydrogels Containing Silk Fibroin: State of the Art and Challenges

Abstract

Abstract Purpose of Review 3D bioprinting of cardiovascular tissues for in vitro and in vivo applications is currently investigated as a potential solution to better mimic the microenvironment typical of the human heart. However, optimal cell viability and tissue vascularization remain two of the main challenges in this regard. Silk fibroin (SF) as a natural biomaterial with unique features supports cell survival and tissue vascularization. This review aims to evaluate the potential of hydrogels containing SF in 3D bioprinting of cardiac tissue that better recapitulate the native cardiac microenvironment. Recent Findings SF hydrogels spontaneously develop nanocrystals, which limit their use for 3D bioprinting applications. Nevertheless, the printability of SF is improved in hybrid hydrogels by mixing it with other natural polymers (such as alginate and gelatin). This is achieved by adding SF with other polymers or by crosslinking it by peroxidase catalysis (i.e., with alginate). Compared to only SF-based hydrogels, hybrid hydrogels provide a durable bioprinted construct with improved mechanical stability and biological properties. To date, studies using cardiac cells in bioprinted SF constructs are yet to be performed. Summary Mixing SF with other polymers in bioprinted hybrid hydrogels improves the printability and durability of 3D bioprinted tissues. Studies using these hydrogels with cardiac cells will be required to evaluate the biocompatibility of SF hybrid hydrogels and to establish their potential use for cardiovascular applications.