Chitosan-based thermosensitive hydrogels (CH) containing hydroxyapatite (HAp) and poly(lactic acid) (PLDLLA) fillers are proposed as an innovative, biomimetic compositions with antimicrobial and bone-forming properties for guided bone regeneration. Their sol-gel transition is initiated at physiological temperature of the human body ensuring hydrogel injectability during its application and further sufficient mechanical support and biological response during the healing course. Modified hydrogels were synthesized and characterized to verify their suitability for clinical trials. Compared to plain hydrogel, the CH_HAp and CH_PLDLLA samples revealed improved mechanical properties, as evidenced by rotational rheology. FTIR analysis proved no existence of chemical interplays between the components. All the tested samples revealed no cytotoxicity against osteoblast-like cell culture as well as antimicrobial features, both crucial from an application perspective. The radiation sterilization dosage was established for the tested samples to maintain sterility for minimum 8 weeks of storage; in the same time causing partial crosslinking of the samples. The hydrogel formulations were used in several clinical trials to treat bone losses in the areas of maxilla, mandible, femur and tibial bones. The medical procedures proved safety, nontoxicity, non-allergenicity, and most importantly osteoinductive properties of the hydrogel formulations. The kinetics of new bone formation was analysed using graphical cross-sections of the anatomical structures obtained from pre- and post-operative CBCT scans [1].

References

M. Dobrzyńska-Mizera, M. Knitter, M. Kamińska, D. Szymanowska, A. Sobczyk-Guzenda, S. Różańska, J. Różański, M. Mikulski, M. Muzalewska, M. Wyleżoł, M. Smuga-Kogut, Z. Modrzejewska Biomater. Sci. 2024, in press.

Acknowledgments

All the authors acknowledge financial support from the National Centre for Research and Development (POIR.01.01.01–00-0960/20) and Poznan University of Technology (grant number 0613/SBAD/4888).