Eggshells, routinely dumped as waste, have been turned into a potential material for bone implants by researchers of the Indian Institute of Technology, Hyderabad (IIT-H) and BR Ambedkar National Institute of Technology (NIT), Jalandhar.

Eggshells are made up largely of calcium (95.1 per cent) along with small amounts of proteins and water. What the IIT & NIT researchers have done is develop a process by which bone implant materials can be synthesized.

They want to produce materials such as β-tricalcium phosphate (β-TCP), a commonly-used bone substitute material from natural sources, without the use of toxic chemicals.

The use of graft materials to heal bone defects has been known for a long time. Sushruta Samhita , an ancient Sanskrit text on medicine and surgery, describes ‘ Asthipoorana ’ or bone grafting in which materials having calcium were combined with the latex of the banyan tree to form bone substitutes, say the researchers.

In modern medicine, damaged and missing bones are replaced with bone from either patient or donor, or by using artificial materials containing calcium, such as Plaster of Paris, and more recently, phosphate compounds like hydroxyapatite and calcium phosphate.

The research, has been carried out by Roopavath Uday Kiran, Bharat B Panigrahi, Subha Narayan Rath of the IITH and Mahesh Kumar Sah of the NIT. The scientific paper has been published in the journal Ceramics International , March 2019 issue.

Effective substitute

According to Uday Kiran, the presence of chemical residues in bone replacement materials, which are toxic in synthetic chemicals, is a concern. For example in β-tricalcium phosphate (β-TCP), is synthesized using nitrate compounds, which if present even in traces, could be dangerous.

In contrast, the bioceramics made from eggshell wastes are predicted to exhibit greater biocompatibility compared to other synthetic powders due to the presence of additional bioactive elemental ions, which are inherently present.

“Eggshells are not only biocompatible, but are also inexpensive and can be obtained in unlimited quantities; millions of tons of eggshells are dumped as waste across the world,” he explained.

The Researchers synthesized pure and thermally stable β-TCP nano powder — powder a hundred thousand times smaller than the width of a single human hair — from eggshells. They used a milling process, called ball milling, to produce these activated calcium phosphate powders. They also studied the effect of processing conditions on the nature of the powder.

Then they fabricated scaffolds using these eggshell derived material and polymer and evaluated cellular response on their surface. Their results show that the eggshell waste are promising enough to replace commercially available β-TCP produced using harmful nitrate precursors and has the capability to develop implantable biomaterial for tissue regeneration.

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