Eggshell‐Based Unconventional Biomaterials for Medical Applications

Eggshells are one of the most abundant byproducts of food processing waste. Each discarded eggshell represents a missed opportunity to convert a no‐cost waste material into a valuable product. Beyond their economic practicality and widespread availability, eggshells possess unique biological and chemical properties that support cell differentiation. Their composition includes biologically active compounds, essential trace elements, and collagenous and noncollagenous elements, mimicking the components of bones, teeth, and skin. Additionally, eggshells serve as a suitable precursor for synthesizing hydroxyapatite, calcium carbonate (CaCO 3 ), and β ‐tricalcium phosphate. Eggshells can be utilized on their own or as derived materials to produce regenerative biocomposite scaffolds for tissue engineering. These scaffolds often exhibit high porosity, excellent biocompatibility, degradability, and mechanical properties. Eggshells and their derivatives have also been employed as carriers for targeted drug delivery systems and in electrochemical biosensors. Eggshells serve as a versatile biomaterial, adept at not only addressing practical gaps but also bridging the divide between sophistication and ease of production. In this review, the chemical composition of eggshells and their numerous applications in hard and soft tissue regeneration, biomolecule delivery, and biosensor development are discussed highlighting their innovative and unconventional use as a natural biomaterial providing solutions for unmet clinical needs.