Scientists invent safe bone graft materials made out of eggshells

An ideal raw material

"Eggshells are an ideal raw material to synthesize bone graft materials as it contains plenty of calcium and phosphorous components,” said the first author of the study, Dr Qianli Ma Qianli Ma the Department of Biomaterials at UiO. “In addition, some trace elements associated with bone regeneration, such as magnesium and strontium, are also found in eggshells."

The team also engineered a novel 3D spheroid model for studying the osteogenic activity of eggshell ACP in vitro. In the model, ACP materials were observed to interact with osteoblasts more realistically and were safe, cell-friendly, and effective in promoting bone regeneration.

"This technique promises to create an unlimited supply of bioactive and sustainable bone graft materials while reducing environmental pollution,” said in the statement senior and corresponding author Professor Håvard Jostein Haugen, who is from the same department at UiO. 

“The osteoblastic spheroids constructed in the study provided a more practical biomaterial research model, reflecting the three-dimensional interactions between cells and biomaterials."

The researchers hope their latest findings will inspire further work on converting ordinary food waste into high-value-added biomaterials. Meanwhile, the team is working towards an ideal in vitro model that can replace in vivo research in animal models.  

The study is published in the KeAi journal Smart Materials in Medicine.

Study abstract:

A multitude of autogenous/allogeneic and semi-synthetic bone graft materials have been developed to reconstruct the defective bone tissue but with high bio-cost and potential environmental pollution. With high calcium content and several trace elements, chicken eggshells are no longer considered as wastes but attractive sources of high-value-added biomaterials. This study used chicken eggshells and synthetic hydroxyapatite (HAp) to synthesize amorphous calcium phosphate (ACP) bone graft materials, namely Control and Eggshell. The physiochemical characteristics, biosafety, and immunocompatibility of synthetic ACP particles were inspected. Their osteogenic activity was further investigated in a novel osteoblastic spheroids model. Eggshell ACP particles exhibited ideal cytocompatibility compared to the control ACP and were more resistant to re-crystallization. In osteoblastic spheroids, Eggshell ACP mediated typical osteogenic mRNA profiles of MC-3T3-E1 cells, accompanied by the increased formation of mineralized nodules and boosted synthesis of ECM proteins represented by OPN and collagen I. This study establishes a promising technique to synthesize stable, safe, and osteoinductive ACP graft particles from eggshell waste. Furthermore, the osteoblastic spheroids constructed in the present study provide a more practical model for biomaterial research, which reflect the three-dimensional interaction between host bone tissue and graft materials more realistically.