Hollow magnetic hydroxyapatite microspheres with hierarchically mesoporous microstructure for pH-responsive drug delivery

Abstract

The hollow magnetic hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂, HAp] microspheres with hierarchically mesoporous structures were hydrothermally fabricated using the similar structured CaCO₃/Fe₃O₄ hollow microspheres as the sacrificial hard-templates. The magnetic property, in vitro biocompatibility, drug loading and release properties in different pH solutions were further investigated. The results showed that the magnetic properties for these biocompatible HAp microspheres could be well adjusted by modulation of the Fe₃O₄ amount, and the drug release rate increased apparently with the decrease of the pH values of the solution medium. The high drug-loading capacity and sustained drug release property suggest that the fabricated multifunctional hollow microspheres have great potential for magnetic and pH responsive drug-delivery applications.