Microwave-assisted synthesis of superparamagnetic mesoporous Co-doped hydroxyapatite nanorods for various biomedical applications

Abstract

Advanced methods to design biocompatible mesoporous superparamagnetic nanoparticles are required for various healthcare applications. This work was designated to synthesize superparamagnetic mesoporous hydroxyapatite (HAp) nanorods (NRs) with the intrinsic pure phase through the doping of cobalt ions inside it. This nanoparticle was synthesized using a black Scallop seashell as a low cost calcium source using oxalic acid as a strong chelating agent via microwave synthesis. The prepared magnetic HAp NRs are analyzed by diverse methods to understand the clarity of phase and its nanostructural features. XRD and EDX results prove that Co is distributed well in the HAp nanoparticles without affecting its structure. The BET surface areas of CoHAp-1, CoHAp-2, and pristine HAp NRs were found to be 69, 126, and 97 m2 g−1, correspondingly. Further, evaluated pore volume of CoHAp-1, CoHAp-2, and pristine HAp NRs are identified to be 0.0275, 0.0349, and 0.0368 cm3 g−1 and also pore diameters were found as 3.02, 4.67, and 4.71 nm. Hence, the HAp mesoporous NRs with higher surface area were achieved with the incorporation of Co in the HAp system. The superparamagnetic characteristics were identified only in the Co-doped HAp samples. The high saturation magnetization of 0.20 Am2 kg−1 was observed with the high doping of Co ions. Toxicity of the pristine and the Co-incorporated HAp samples were evaluated using zebrafish. The toxicity result reveals that Co incorporations in HAp do not affect significantly the biocompatible nature compared to the pristine HAp sample. Antibacterial test shows excellent antibacterial activities for Co-HAp samples among different pathogens. Hence, the approach of oxalic acid-associated microwave mediated synthesis of intrinsic mesoporous superparamagnetic HAp NRs from naturally occurring seashells as a precursor can be a superior method for obtaining nanomaterials towards various applications like magnetic resonance imaging, targeting of drug, hyperthermia, and cancer treatments.