Layered double Hydroxides for biomedical purposes: Sustainable and green synthesis

Layered double hydroxides (LDH) are interesting nanomaterials in biomedical field due to their degradability and their composition in bioactive ions. Their synthesis often requires numerous steps, including several purifications, causing waste of water and harsh salts effluents. Therefore, the aims of this work are the development of innovative, sustainable and green synthetic routes to manufacture LDH and their biological characterizations in view of their use in the biomedical field. The LDH were synthesized using two different methods, ammonia- based coprecipitation and microwave and hydrothermal-assisted urea hydrolysis. These strategies were improved by reducing the synthetic and purification phases in view of a single-step continuous process. Different chemical compositions were considered, including ions of biological interest, like zinc and copper. The obtained LDH were then characterized, both before and after washing, to evaluate the impact of the adapted synthetic process on the quality of the materials. Physico-chemical and biological properties were assessed. The tailoring of the synthetic routes and the reduction of the synthetic steps did not affect the quality of the samples. Moreover, the LDH were characterized by high degree of biocompatibility towards Caco-2, tenocytes and fibroblasts, proving that the synthetic approaches used for the LDH synthesis guarantee promising materials to be used in the biomedical field.