title: Glycine-functionalized Fe3O4@TiO2:Er(3+),Yb(3+) nanocarrier for microwave-triggered controllable drug release and study on mechanism of loading/release process using microcalorimetry.
abstract: OBJECTIVE
  The current study aimed at developing microwave-triggered controlled-release drug delivery systems using glycine-modified Fe3O4@TiO2:Er(3+),Yb(3+) multifunctional core-shell nanoparticles. We also studied the drug loading and release mechanisms by means of microcalorimetry.
  
  
  METHODS
  We used hydrothermal method to prepare glycine-functionalized Fe3O4@TiO2:Er(3+),Yb(3+) multifunctional nanoparticles. The controlled release of the Fe3O4@TiO2:Er(3+),Yb(3+)-glycine-VP16 triggered by microwave was determined with ultraviolet-visible spectroscopic analysis. We studied the cytotoxicity of the nanocarrier by MTT assay.
  
  
  RESULTS
  The thermodynamic parameter values (ΔH = -17.46 kJ mol(-1), ΔS = -365.20 kJ mol(-1)) showed that the main interaction between the carrier and drug molecules is hydrogen bonding. The molar enthalpy (ΔH) of the drug-release process was 72.01 kJ mol(-1), which indicates an endothermic process. This suggests that drug release can be controlled by microwave heating. The release profile can be controlled by the duration and number of cycles of microwave application. The particles also exhibit good magnetization and upconversion luminescence properties, which will allow simultaneous targeting and monitoring of the loaded drug.
  
  
  CONCLUSIONS
  The modification of glycine and the introduction of absorbing material not only increased the load properties of the composite materials but also realized the microwave-stimulated anticancer drug controlled release.
authors.affiliation: Northwest University, School of Chemistry and Materials Science, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), Shaanxi Key Laboratory of Physico-Inorganic Chemistry , Xi'an 710069 , PR China +86 029 8830 2604 ; +86 029 8830 3798 ; cuibin@nwu.edu.cn.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Peng
authors.forename: Bin
authors.initials: B
authors.lastname: Cui
authors.forename: Weiwei
authors.initials: W
authors.lastname: Zhao
authors.forename: Yingsai
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhuguo
authors.initials: Z
authors.lastname: Chang
authors.forename: Yaoyu
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage*; D003692:Delayed-Action Preparations; D016503:Drug Delivery Systems; D065546:Drug Liberation; D005047:Etoposide / Q000008:administration & dosage*; D005998:Glycine / Q000737:chemistry; D006801:Humans; D061986:MCF-7 Cells; D008872:Microwaves; D053758:Nanoparticles; D014025:Titanium / Q000737:chemistry
chemical_list: D000970:Antineoplastic Agents; D003692:Delayed-Action Preparations; C009495:titanium dioxide; D005047:Etoposide; D014025:Titanium; D005998:Glycine
keywords: Fe3O4@TiO2:Er3+,Yb3+; drug controlled release; magnetic; microcalorimetry; microwave-stimulated release; upconversion luminescent