A multifunctional β-CD-modified Fe3O4@ZnO:Er3+,Yb3+ nanocarrier for antitumor drug delivery and microwave-triggered drug release

We constructed a novel core shell structured Fe3O4@ZnO:Er3+,Yb3+@(beta-CD) nanoparticles used as drug carrier to investigate the loading and controllable release properties of the chemotherapeutic drug etoposide (VP-16). The cavity of beta-cyclodextrin is chemically inert, it can store etoposide molecules by means of hydrophobic interactions. The Fe3O4 core and ZnO:Er3+,Yb3+ shell functioned successfully for magnetic targeting and upconversion fluorescence imaging, respectively. In addition, the ZnO:Er3+,Yb3+ shell acts as a good microwave absorber with excellent microwave thermal response property for microwave triggered drug release (the VP-16 release of 18% under microwave irradiation for 15 min outclass the 2% within 6 h without microwave irradiation release). The release profile could be controlled by the duration and number of cycles of microwave application. This material therefore promises to be a useful noninvasive, externally controlled drug-delivery system in cancer therapy. (C) 2014 Elsevier B.V. All rights reserved.