Eggshell Waste: A Gold Mine for Sustainable Bioceramics

Bioceramics derived from natural sources such as eggshell, bovine bone, fish bone, etc. have the benefit of inheriting some of the properties of the raw materials like optimal composition, similar morphology, etc., along with the advantages of unlimited worldwide availability at a very low raw material cost. The eggshell waste is an inexpensive source of calcium, and so, a great deal of effort has been made to exploit this resource as value-added calcium phosphates (CaP) such as hydroxyapatite, tricalcium phosphate, tetracalcium phosphate, etc., which are the most widely used for bone and dental applications. Eggshell-derived CaPs were found to have minor amounts of biologically relevant ions inherited from the eggshell. As these ions are crucial for bio-mineralization of eggshell, the potential of eggshell derived multi-ion-substituted CaPs for bone regenerative applications has been reviewed. The development of eggshell-derived CaP nanocarriers for the delivery of drugs and protein has been summarised. The role of CaP precursors from eggshells in improving the material and biological properties of bone cement formulations has been highlighted. The advantages of eggshell CaP-based scaffolds in tissue engineering and regenerative medicine have also been summarised. Overall, the current article aims to provide an insight into the recent medical applications of eggshell-based calcium phosphate bioceramics.