Thermoset composite hydrogels for bone/intervertebral disc interface

• Morphology of needle-like phases influences the mechanical response of PHEMA.
• Mechanical properties can be tailored as a function of polymer/ceramic composition.
• Mechanical response of TCH are compatible with bone/IVD interface.

We introduce an interesting strategy to develop thermoset composite hydrogels (TCH) integrating calcium deficient hydroxyapatite (CDHA) into poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogels. The process consists in two feasible steps: (1) the temperature driven polymerization of hydroxyethylmetacrilate (HEMa) in water or glycerol solution and, (2) the hardening reaction of CDHA triggered by hydrolysis of α-tricalcium phosphates (α-TCP) in NaHPO4 water solution at body temperature. SEM investigation show that final morphology of composite is significantly affected by monomer concentration and used solvents (i.e, water or Glycerol). These results are also in agreement with the characterization of mechanical response under compression performed of different TCH typologies. All the reported results confirm that TCH obtained by thermal curing and hardening reaction may represent a promising bone-like material with interesting properties to mimic the native vertebrae/annulus interface for a non-invasive IVD repair strategies.