Injectable composite gels containing magnesium phosphate for bone regeneration: Analysis of hydration and in vivo...

The challenge of effectively distributing inorganic nanoparticles for bone regeneration while ensuring their retention at the defect site remains a substantial barrier in tissue engineering. To address this issue, we created injectable hybrid hydrogels containing zinc-doped magnesium phosphate (ZnMgP) and poly(N-acryloyl glycinamide). We aimed to ensure proper hydration of the material interface by promoting cell growth on it. To assess their structural integrity and hydration capabilities, the hydrogels were evaluated using various techniques, such as X-ray diffraction, Fourier-transform infrared spectroscopy, and differential scanning calorimetry (DSC). Power analysis was used to determine an adequate sample size, allocating six animals to each experimental group. Notably, DSC investigations demonstrated stable intermediate water states, with nonfreezing water levels reaching a high of 0.45 g/g and a total water content of 0.65 g/g. In vivo tests conducted on Wistar rats revealed significant new bone growth after 8 weeks, and tissue samples indicated the presence of developed mineralized tissue and blood vessel formation at the injury sites treated with various types of hydrogels, especially the one containing 7 wt% of ZnO. These findings established a link between hydration characteristics and biological performance of the fabricated hybrid hydrogels. The outcomes of this study suggest that the hydrogels that were created are beneficial for the regeneration of bone tissue.