Using eggshells for bone grafts

This new material provides a cost-effective, ethical, and environmentally friendly alternative to traditional bone transplants

Spotted: Bone grafts are considered to be the gold standard in terms of repairing and reconstructing damaged bones. These can either be autologous, where a patient’s own tissue is used, or allogeneic, where the tissue is taken from another person. But limited supply, donor-site complications, and risk of disease transmission can often prevent allogeneic grafts from being used. Xenogeneic bone grafts, where the graft is taken from another species, represent a feasible alternative. But, because xenograft materials come from mammal tissue, it raises ethical questions surrounding animal welfare.

To find a safe, adaptable, and environmentally friendly alternative, a team of researchers has developed a method to convert eggshells into endotoxin-free and immunocompatible amorphous calcium phosphate (ACP) particles.

First the shells were heated, then mixed with distilled water and phosphoric acid. The precipitate was then filtered and washed, before being submerged in liquid nitrogen. The resulting ACP particles are essential to forming hard and strong bone and can therefore be used as an ideal bone substitute.

As well as containing plenty of calcium and phosphorous, Dr Qianli Ma – the study’s lead author – highlights that eggshells are also an ideal raw material because they contain traces of magnesium and strontium, which are associated with healthy bone regeneration. The team also created a novel 3D spheroid model, which allows the activity of eggshell ACP to be studied in vitro. With the model, the researchers could observe how the ACP materials would actually interact with osteoblasts, and they were found to be safe and effective in promoting bone regeneration. 

If scaled successfully, this new technique could enable an unlimited supply of sustainable bone graft materials, while reducing the volume of eggshells going to waste. The scientists hope their latest findings inspire additional research into the conversion of food waste into high-value biomaterials.  

Eggshells are not only being used in the medical field. Springwise has also spotted a design studio creating wall tiles from discarded eggshells, and another that has transformed the waste into car interiors.

Written By: Anam Alam