Effects of microwave processing parameters on the properties of nanohydroxyapatite: Structural, spectroscopic, hardness, and toxicity studies

This paper analyzed the effects of the processing parameters on the structural, spectroscopic, and hardness properties and toxicity of nanohydroxyapatite (nanoHAP) materials, specifically in terms of low-power short duration microwave irradiation. NanoHAP compounds were synthesized from duck eggshells (a bio-based calcium source) and phosphoric acid via a wet precipitation method and subsequent treatment by microwave irradiation. Three different power inputs of 40, 200, and 400 W were used for the microwave tests, which were conducted for durations of 35, 40, and 45 min. The results confirmed the benefits of microwave treatments in terms of rapid heating, reduced reaction time, and high throughput. The existence of pure nanoHAP was confirmed by an X-ray diffractogram, and the high energy emitted by the microwave irradiation combined with an extended reaction time was proven to further transform eggshell calcium (CaO) into nanoHAP. The shift toward narrower and smaller particles with increasing irradiation power and treatment duration was confirmed via scanning electron microscopy, and an increase in hardness with extended irradiation was demonstrated. A toxicity analysis conducted on human embryonic cells confirmed high cell viability after incubation with nanoHAP. This indicates that nanoHAP obtained from microwave irradiation treatment has the potential to be used as a biomaterial.

Automated summary

This paper investigates the effects of microwave irradiation treatment on the properties of nanohydroxyapatite (nanoHAP) materials, highlighting the advantages of rapid heating, reduced reaction time, and increased productivity. Microwave irradiation is shown to facilitate the transformation of eggshell calcium into nanoHAP and the production of smaller particles with extended irradiation. Toxicity analysis reveals high cell viability of human embryonic cells after exposure to nanoHAP obtained from microwave irradiation treatment, indicating its potential as a biomaterial.