Bioactive injectable hydrogels using ionic liquids – IONIBIOGEL

Today regenerative medicine is moving towards the development of less and less invasive surgical techniques with the objective of reducing morbidity and the duration of hospitalisation. This quest for minimally-invasive surgery has motivated the development of injectable matrices for bone and cartilage tissue engineering. Once implanted, these injectable matrices must also be able to set, acquire the desired form, and present mechanical properties in relation to the tissue to be repaired. Polymers with good viscosifying capabilities in water can be used to make hydrogels via physical, ionic, or covalent cross-linking. In this case, they make true 3D macromolecular networks comparable to the extracellular matrix (ECM). Our current field of research is the regeneration of skeletal tissues such as bone and cartilage; we develop hydrogels and biomaterials made from biopolymers as supports for tissue engineering in order to carry out regenerative medicine. Since the cartilage is non-vascularised, its regeneration also requires tissue engineering specific approach. The IONIBIOGEL project intends to develop innovative chemistry on sugar based molecules using ionic liquids. Previously an injectable cellulose-based hydrogel bearing siloxane groups (Si-HPMC hydrogel) has been developed and patented. Recent studies made by the partners of the project have shown that the incorporation of marine polysaccharides in this Si-HPMC hydrogel significantly improved its mechanical and biological properties. These marine polysaccharides can participate in many biological processes through interactions with growth factors (crinopexy). The degree of sulphation of polysaccharides is a key parameter for biological activity as well as are also positions of sulphate groups. We will modify different polysaccharides to build up complex hydrogels. The targeted modifications will be the depolymerization and the functionalization by grafting either siloxane groups and/or sulphate groups. These modified polysaccharides will give new materials, more stable and endowed with appropriate chemical, mechanical and biological properties. These complex hybrid constructions will allow us to understand the effect of the ECM features on the cell 3D environment, resulting in specific cellular differentiation, mobility, and multiplication. Innovative strategies for the creation of ECM suited to osteoarticular tissue engineering will be thus elaborated. Furthermore, the production of in vivo models will give an in-depth basic knowledge of the in vivo cellular macro- and nano-metric processes and of the complex networks of living cells.