Hydroxyapatite nanosheet-assembled porous hollow microspheres: DNA-templated hydrothermal synthesis, drug delivery and protein adsorption

Porous hollow microspheres of hydroxyapatite (HAP) are an ideal biomaterial due to their excellent biocompatibility and hollow structure. Herein, we report a novel DNA-templated hydrothermal strategy for the synthesis of HAP nanosheet-assembled hollow microspheres with a nanoporous structure. The as-prepared HAP porous hollow microspheres consist of HAP nanosheets as the building blocks with an average thickness of about 20 nm, and the diameters of the HAP porous hollow microspheres are in the range 2.5-4.5 mu m, with an average pore size of about 21.8 nm. The as-prepared HAP porous hollow microspheres are explored for potential applications in drug delivery, and protein adsorption and release. The as-prepared HAP porous hollow microspheres show a relatively high drug loading capacity and protein adsorption ability, and sustained drug and protein release, using ibuprofen as a model drug and hemoglobin (Hb) as a model protein. The experiments indicate that the as-prepared HAP porous hollow microspheres are promising for applications in biomedical fields such as drug delivery and protein adsorption.