Nanostructured hollow hydroxyapatite fabrication by carbon templating for enhanced drug delivery and biomedical applications

Abstract Fabrication of nanostructured materials with multifunctional properties and improved biocompatibility have immense potential for biomedical applications. The novelty of this research is to synthesize nanostructured hollow hydroxyapatite (H-HAp) for enhanced drug delivery applications. The nano hollow structure synthesis mechanism involves the controlled precipitation of calcium and phosphate ions over a pre-synthesized nano carbon template, followed by calcination to eliminate the core carbon structure. The synthesized nano-structured H-HAp was analyzed to determine its chemical, elemental, structural, and morphological characteristics by different spectroscopic, gravimetric, and electron microscopy techniques. The potential advances of H-HAp nanoparticles in biological applications were studied by using MDA-MB-231 breast cancer cell lines, and drug kinetics experiments. The cytotoxicity and the efficacy of H-HAp as a drug carrier agent were studied by MTT and fluorescence staining assay. The comparative drug loading/releasing kinetics were studied using nanostructured H-HAp and HAp with the model drug doxorubicin (DOX) and bovine serum albumin (BSA) protein. The synthesized nanostructured materials show relatively enhanced drug (DOX = ∼53.33%) and protein (BSA = ∼43.06%) loading capacities compared to conventional HAp (DOX = ∼46% and BSA = ∼23.62%). The H-HAp nanostructured system shows a pH-dependent sustained in vitro release behavior of model drug molecules. The novelty of this study relies on its facile synthesis mechanism to fabricate a hollow nano HAp structure, which differs from limited reported articles based mostly on microstructure H-HAp for biomedical applications.