3D bioprinted silk-reinforced Alginate-Gellan Gum constructs for cartilage regeneration

Even though a substantial amount of research has been undertaken in the domains of bioprinting over the last few years, various challenges exist concerning printability. One of the grave challenges in developing a bioink with superior printability is the constraint of material availability, cross-linking, and other processing parameters that should warrant adequate functioning post bioprinting. This study demonstrates the development of a multicomponent shear-thinning bioink comprising Alginate and Gellan Gum with good mechanical, biological, and adequate printing properties. The addition of two types of silk nanoparticles (SNP), native and regenerated, acted as a reinforcement to the bioink, enhancing its printability. Additionally, silk fibroin solution was added to the bioink that served as a control apart from SNP. The addition of cationic SNP (native) to the anionic polymer mixture of Alginate-Gellan Gum exhibited a remarkable increase in the viscosity, storage modulus and mechanical property compared to the other experimental sets. Molecular characterization studies involving Real-Time PCR, gene expression, immunofluorescence, and histology analysis depicted enhanced chondrogenesis in the bioprinted construct containing the silk fibroin solution. The incorporated SNPs resulted in extracellular matrix secretion towards chondrogenesis of articular cartilage. Taken together, the method's broad applicability is likely to propel the field closer to the goal of precision bioprinting.