IRRADIATED κ-CARRAGEENAN AND PVA 3D PRINTED SCAFFOLD FOR OSTEOCHONDRAL TISSUE RECONSTRUCTION

Abstract

κ-Carrageenan (κ-C) is a sulfated polygalactan obtained from red algae with 25 to 30% of ester-sulfate content and an average relative molecular mass well above 100 kDa [1] with an inherent ability to form strong networks in mild conditions [2]. κ-C is water-soluble at temperature above 60 °C and can set into stable hydrogels with decreasing temperature. This polysaccharide resembles the glycosaminoglycans (GAGs) which are the central constituents of connective tissues, an interesting property considering that hydrogels are often thought as bio-inks of 3D printing processes that aim to reconstruct the extracellular matrix of relatively soft tissues. The possibility of controlling the printing process on the basis of a computer- aided design (CAD) of the patient’s damaged or missing body part holds the promise of manufacturing patient-specific structures. κ-C in blends with other more resilient polymers, like polyvinyl alcohol (PVA), can improve its mechanical properties and create porosity [3]. PVA is a biocompatible polymer that can form gels by either freeze-thawing treatments and/or high-energy irradiation, with no recourse to crosslinking agents. Conversely, carrageenans irradiated in gel states or in aqueous solution can be depolymerized to form shorter fragments with reported antioxidant properties, that can promote the recovery process of damaged tissues [4]. Indeed, even the scaffolds made with the most biocompatible polymers can suffer from immune rejection, subsequent long-term oxidative stress and inflammation, if the polymers are foreign to the native tissue microenvironment. Therefore, incorporating antioxidant components into the scaffolds may effectively counterbalance the overproduction of ROS, maintaining redox balance and ultimately restoring cell health. Our study explores the influence of simultaneous PVA crosslinking and κ-C fragmentation effects induced by high energy irradiation on κ-C/PVA 3D printed hydrogel scaffolds for patient- personalized osteochondral tissue reconstruction. [1] J. Necas, L. Bartosikova, Veterinarni Medicina, 2013, 58, 187–205. [2] J.T. Oliveira, R.L. Reis, J Tissue Eng Regen Med. 2011, 5, 421-36. [3] E. Muscolino, et al., Int. J. Biol. Macromol., 2022, 222, 1861-1875. [4] L. Relleve, L. Abad, Radiat. Phys. Chem., 2015, 112, 40-48..