Fine property-tuning through Ca content control in a facile synthesis of glasses-based self-setting injectable hydrogel

Self-setting injectable composite hydrogels are promising materials in tissue engineering. In this study a facile synthetic approach was designed based on traditional sol-gel method to produce particulate calcium aluminosilicate-type glasses, which were then formulated with potassium alginate to form a self-setting injectable hydrogel. In order to control the setting-time and mechanical properties of the composite materials, a series of samples were produced with different starting chemical composition. The change in chemical composition and morphology of the glass particles in response to varying initial Ca2+ content were further elucidated by a combination of EM, XRF and NMR spectroscopy, revealing that the binary aluminosilicate glass was preferably formed when low Ca content (<20%) was used in the formulation. At higher Ca content (>30%), calcium aluminosilicates were predominantly formed due to the change in the type of zeolite precursor formed during the low temperature nucleation process in the sol-gel approach. It was also found the hardening times of the alginate gels was positively correlated to the mole ratio of Ca/Al due to high acid resistance of high coordination number Al species. For hydrogels made with glass particle additions, the mechanical strengths were also positively correlated with the Ca/Al ratio for all formulations. (C) 2021 The Authors. Published by Elsevier Ltd.

Automated summary

A novel synthetic approach for injectable hydrogels was designed, with the ability to control setting time and mechanical properties by adjusting the chemical composition. The study also revealed a positive correlation between the Ca/Al ratio and the hardening time and mechanical strength of alginate gels.