"A new Gellan Gum/Lignin bioink: a promising route for cartilage repair
Maria A. Bonifacioa,, Stefania Cometab, Andrea Cochisc, Annachiara Scalzoned, Piergiorgio Gentiled, Alessandro C. Scaliac, Lia Rimondinic, Piero Mastrorillie, Elvira De Giglioa
aDepartment of Chemistry, University of Bari, Via Orabona 4, 70126 Bari, Italy
bJaber Innovation s.r.l., Via Calcutta 8, 00144 Rome, Italy
cCenter for Translational Research on Autoimmune and Allergic Disease, CAAD, Department of Health Sciences, 28100 Novara, Italy
dNewcastle University, School of Engineering, Claremont Road, NE1 7RU Newcastle upon Tyne, United Kingdom
eDICATECh Department Politecnico di Bari, Via Orabona 4, 70126 Bari, Italy
Recent developments in tissue engineering have been addressed to the development of cartilage-replacing hydrogels based on gellan gum, a bacterial exopolysaccharide, in combination with different polymers and/or fibers to enhance its mechanical and biological performances [1, 2]. In this respect, our research group focused the attention on gellan gum-based hydrogels reinforced with different inorganic clays as cartilage substitutes [3, 4]. In this study, a composite hydrogel, based on a blend of two gellan gums with different acyl content embedding lignin, was developed for the regeneration of cartilage tissue. Different amounts of lignin (up to 0.4% w/v) were loaded into the polymeric matrix and the resulting hydrogels were physically crosslinked with magnesium ions. The physico-chemical characterizations established that, even if no chemical interaction between lignin and the polysaccharides was detected by XPS and SS-NMR analyses, lignin release in PBS resulted negligible and that lignin achieved up to 80% of ascorbic acid’s radical scavenging activity in vitro on DPPH and ABTS radicals. Moreover, the formulated hydrogels were able to recover their original shape after compression. Lignin exploitation resulted cytocompatible as the viability of human mesenchymal stem cells (hMSC) 3D-seeded onto scaffolds resulted comparable to the lignin-free control hydrogel (>70% viable cells, p>0.05); moreover, the 0.4% lignin composites significantly improved the hMSC 3D-constructs chondrogenesis bringing to a significant (p<0.05) up-regulation of the collagen type II, aggrecan and SOX 9 chondrogenic genes. The presence of lignin conferred bacteriostatic properties to the hydrogel too, thus reducing the proliferation of the joint pathogens Staphylococcus aureus and Staphylococcus epidermidis of >2 logs in comparison to the lignin-free control hydrogel. Finally, cellularized 3D constructs were manufactured via 3D bioprinting confirming the processability of the hydrogel formulation as a bioink and its unique biological features for creating a physiological milieu for cell growth.
1- Kim, W., Choi, J.H., Kim, P., Youn, J., Song, J.E., Motta, A., Migliaresi, C., Khang G. (2021). Journal of Tissue Engineering and Regenerative Medicine 15.11, 936-947.
2- Lee, S., Choi, J.H., Park, A., Rim, M., Youn, J., Lee, W., Song, J.E., Khang, G. (2020). International Journal of Biological Macromolecules, 158, 452-460.
3- Bonifacio M.A., Cometa, S., Cochis, A., Gentile, P., Ferreira, A. M., Azzimonti, B., Procino, G., Ceci, E., Rimondini, L., & De Giglio, E. (2018). Carbohydrate Polymers, 198, 462–472.
4- Bonifacio, M. A., Cochis, A., Cometa, S., Gentile, P., Scalzone, A., Scalia, A. C., Rimondini, L., & De Giglio, E. (2020). Carbohydrate Polymers, 245, 116410.