We may soon be giving our unwanted eggshells to science, thanks to new research that has used the humble chicken eggshell to create a new bioactive material for making safe, effective bone grafts.
Bone grafting is a common way to fill voids or gaps in bones caused by trauma or surgery such as tumor resection. Worldwide, about two million bone grafts are performed annually in orthopedic surgery, neurosurgery, plastic surgery and dental surgery.
Bone graft materials come from various sources. Autologous grafts use bone from the person receiving the graft. Allogeneic grafts use donor bone harvested during surgical procedures such as hip replacements and sanitized for use in others. Xenogeneic bone is derived from non-living bone of another species, usually cows or pigs, and processed at high temperatures to avoid immune rejection and contamination.
Due to their ability to generate new bone, autologous and allogeneic grafts remain the gold standard. While xenogeneic grafts are a feasible alternative, they rely on the availability of animal-based materials, which carry a high environmental cost and raise ethical concerns. To come up with a safe and effective xenograft material, researchers turned to the humble yet abundant chicken egg.
The researchers developed a novel method of dissolution-precipitation to create amorphous calcium phosphate (ACP) particles from chicken eggshells. ACP is essential to the formation of mineralized – that is, hard and strong – bone and has previously been used as a bone substitute because of its components.
“Eggshells is an ideal raw material to synthesize bone graft materials as it contains plenty of calcium and phosphorous components,” said Qianli Ma, lead author of the study. “In addition, some trace elements associated with bone regeneration, such as magnesium and strontium, are also found in eggshell.”
To create their ‘eggshell ACP,’ the researchers first heated eggshells at 1,652 °F (900 °C) for an hour to decompose the organic matter and transform calcium carbonate into calcium oxide. The calcium oxide was added to distilled water, creating a white suspension. Phosphoric acid was stirred into the suspension, and the ACP precipitate was filtered and washed with distilled water before being immersed in liquid nitrogen.
In another first, the researchers embedded the ACP particles into a 3D spheroid to better analyze the bone-forming (osteogenic) activity of the particles through the interaction between host bone tissue and graft materials.
They found that in vitro eggshell ACP particles interacted realistically with osteoblasts, the cells that build bone. In addition, they were nontoxic, immunocompatible, and effective in promoting bone regeneration.
“This technique promises to create an unlimited supply of bioactive and sustainable bone graft materials while reducing the environmental pollution,” said Håvard Jostein Haugen, corresponding author of the study. “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 that their findings will encourage more research into the use of ordinary food waste as a biomaterial.
The study was published in the journal Smart Materials in Medicine.
Source: KeAI Communications Co Ltd via EurekAlert!