Conversion of waste sea shell (Anadara granosa) into valuable nanohydroxyapatite (nHAp) for biomedical applications

Million tons of sea shells are produced as bio-waste around the world every day and these create odors and promote microbial growth, and emit CO2 in lesser extent as they biodegrade, and lead to environmental pollution. To reduce the pollution and give good value to waste shells, nanohydroxyapatite (nHAp) has been extracted from Anadara granosa waste with and without polymers by eco-friendly, product free and cost - effective microwave irradiation method. These nanoparticles have been characterized by FT-IR, XRD, SEM with EDX, TEM and Antibacterial activity. The FT- IR shows that aragonite into calcite phase change is observed at 500 °C in the raw sample. The presence of OH, HPO42− and PO43− absorption bands indicate the formation of HAp. Size of the particle, phase conformation and status of other phase (impurity) are analyzed. All the samples are in nanosize and they do not contain any discernible crystalline impurity. SEM and TEM analyses show that nHAp has particle like structure, when presence of polymer, rod like hexagonal structure is observed. The antibacterial effect of capped and uncapped HAp powder against pathogen bacterial strains Escherichia coli and Bacillaus cereus show the excellent antibacterial activity. The best nHAp composite is applied in the Dentin application.