Bio-based hydrogels scaffolds with lignin particles applied to tissue engineering

Tissue and organ failure due to disease, injury, and defects has become a major health concern. Organs /tissue donation is the clinical way to amend the situation, however, there is a high number of people on the waiting list for transplants, in addition to the shortage of organ donors. Regarding this, tissue engineering appears as a promising solution. The use of bio-based materials for tissue engineering applications has gained extensive interest because they are non-toxic, biocompatible, and renewable. In this study, cellulose nanofibrils, lignin nanoparticles, and tragacanth gum were used to prepare multicomponent hydrogels for 3D printing scaffolds with biocompatible properties to apply in soft tissue replacement. Cellulose nanofibrils (CNF) have exceptional water-binding capacity and produce stable hydrogels with shear-thinning behavior hence attracted interest for 3D bioprinting. Lignin is interesting for biomedical applications due to its antimicrobial and antioxidant properties. Tragacanth gum (TG) is non-toxic, safe for ingestion, and has good rheological properties, however, its potential biomedical applications haven't been fully investigated. Results of our work showed that rheological behavior was improved by adding TG to the hydrogel composition. Similar outcome was observed for scaffold swelling capacity and degradation rate, the properties were improved with increasing of TG content in the hydrogels. Values of the compressive Young’s moduli for the hydrogels allowed to classify them as soft gels on the level between skin and muscle tissues. The properties combination of these materials makes plant-based hydrogels appealing for designing materials with potential of improving patients’ lives through regenerative medicine.