Hybrid Pectin-Fibroin Microgels with Supramolecular and Covalent Cross-Links

Sugar beet pectin, an anionic polysaccharide, and silk fibroin, a high molecular weight protein, undergo gelation through ionic interactions and conformational changes, leading to hydrogel formation. Although many studies have focused on bulk gel systems involving polysaccharides and proteins, more research is needed to investigate their properties at the microscale level. In this context, we have developed a microgel system based on a pectin/fibroin combination and investigated its properties. We focused on two gelation mechanisms: physical cross-linking and enzymatic covalent cross-linking. The pectin/fibroin microgels were fabricated using droplet-based microfluidics, and the secondary structure, mechanical properties, and degradation profiles were investigated. Our experimental results show that the microgels exhibit an ordered β-sheet structure, a Young's modulus in the range of 10 to 20 kPa, and that degradation can be promoted using protease enzymes. Finally, the biocompatibility of the microgels is assessed using the Alamar Blue cell viability assay with human pulmonary fibroblasts (HPFs). This research presents a highly functional hybrid biomaterial produced from waste products and a structural protein, demonstrating its cell compatibility and potential in tissue engineering applications.