title: Core-shell hollow microspheres of magnetic iron oxide@amorphous calcium phosphate: synthesis using adenosine 5'-triphosphate and application in pH-responsive drug delivery.
abstract: Drug nanocarriers with magnetic targeting and pH-responsive drug-release behavior are promising for applications in controlled drug delivery. Magnetic iron oxides show excellent magnetism, but their application in drug delivery is limited by low drug-loading capacity and poor control over drug release. Herein, core-shell hollow microspheres of magnetic iron oxide@amorphous calcium phosphate (MIO@ACP) were prepared and investigated as magnetic, pH-responsive drug nanocarriers. Hollow microspheres of magnetic iron oxide (HMIOs) were prepared by etching solid MIO microspheres in hydrochloric acid/ethanol solution. After loading a drug into the HMIOs, the drug-loaded HMIOs were coated with a protective layer of ACP by using adenosine 5'-triphosphate (ATP) disodium salt (Na2 ATP) as stabilizer, and drug-loaded core-shell hollow microspheres of MIO@ACP (HMIOs/drug/ACP) were obtained. The as-prepared HMIOs/drug/ACP drug-delivery system exhibits superparamagnetism and pH-responsive drug-release behavior. In a medium with pH 7.4, drug release was slow, but it was significantly accelerated at pH 4.5 due to dissolution of the ACP shell. Docetaxel-loaded core-shell hollow microspheres of MIO@ACP exhibited high anticancer activity.
authors.affiliation: State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (P. R. China).
authors.forename: Bing-Qiang
authors.initials: BQ
authors.lastname: Lu
authors.forename: Ying-Jie
authors.initials: YJ
authors.lastname: Zhu
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
authors.forename: Chao
authors.initials: C
authors.lastname: Qi
authors.forename: Xin-Yu
authors.initials: XY
authors.lastname: Zhao
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry*; D002130:Calcium Phosphates / Q000138:chemical synthesis*; D004337:Drug Carriers; D005290:Ferric Compounds / Q000138:chemical synthesis*; D006863:Hydrogen-Ion Concentration; D046529:Microscopy, Electron, Transmission; D008863:Microspheres
chemical_list: D002130:Calcium Phosphates; D004337:Drug Carriers; D005290:Ferric Compounds; C000499:ferric oxide; D000255:Adenosine Triphosphate; C020243:calcium phosphate
keywords: core-shell structures; drug delivery; iron oxides; magnetic properties; nanostructures