title: Evaluation of superparamagnetic iron oxide-polymer composite microcapsules for magnetic resonance-guided high-intensity focused ultrasound cancer surgery.
abstract: BACKGROUND
  Superparamagnetic poly (lactic-co-glycolic acid) (PLGA)-coated Fe3O4 microcapsules are receiving increased attention as potential diagnostic and therapeutic modalities in the field of oncology. In this study, PLGA-coated Fe3O4 microcapsules were combined with a magnetic resonance imaging-guided high-intensity focused ultrasound (MR-guided HIFU) platform, with the objective of investigating the effects of these composite microcapsules regarding MR-guided HIFU liver cancer surgery in vivo.
  
  
  METHODS
  PLGA-coated Fe3O4 microcapsules consisting of a liquid core and a PLGA-Fe3O4 shell were fabricated using a modified double emulsion evaporation method. Their acute biosafety was confirmed in vitro using MDA cells and in vivo using rabbits. To perform MR-guided HIFU surgery, the microcapsules were intravenously injected into a rabbit liver tumor model before MR-guided HIFU. T2-weighted images and MR signal intensity in normal liver parenchyma and tumor tissue were acquired before and after injection, to assess the MR imaging ability of the microcapsules. After MR-guided HIFU ablation tissue temperature mapping, the coagulative volume and histopathology of the tumor tissue were analyzed to investigate the ablation effects of MR-guided HIFUs.
  
  
  RESULTS
  Scanning and transmission electron microscopy showed that the microcapsules displayed a spherical morphology and a shell-core structure (mean diameter, 587 nm). The hysteresis curve displayed the typical superparamagnetic properties of the microcapsules, which are critical to their application in MR-guided HIFU surgery. In MR-guided HIFU surgery, these microcapsules functioned as an MRI contrast agent, induced significant hyperthermal enhancement (P < 0.05) and significantly enhanced the volume of coagulative necrosis (P < 0.05).
  
  
  CONCLUSIONS
  The administration of PLGA-coated Fe3O4 microcapsules is a potentially synergistic technique regarding the enhancement of MR-guided HIFU cancer surgery.
authors.forename: Yang
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Second Affiliated Hospital, Institute of Ultrasound Imaging, Chongqing Medical University, Chongqing, P, R, China. zhengyuanyi@gmail.com.
authors.forename: Yuanyi
authors.initials: Y
authors.lastname: Zheng
authors.forename: Pan
authors.initials: P
authors.lastname: Li
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Niu
authors.forename: Yuping
authors.initials: Y
authors.lastname: Gong
authors.forename: Rongzhong
authors.initials: R
authors.lastname: Huang
authors.forename: Zhibiao
authors.initials: Z
authors.lastname: Wang
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Wang
authors.forename: Haitao
authors.initials: H
authors.lastname: Ran
mesh_terms: D000818:Animals; D002214:Capsules / Q000008:administration & dosage / Q000737:chemistry* / Q000627:therapeutic use*; D004195:Disease Models, Animal; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D008113:Liver Neoplasms / Q000473:pathology / Q000628:therapy* / Q000648:ultrastructure; D011108:Polymers / Q000737:chemistry*; D011817:Rabbits; D013997:Time Factors
chemical_list: D002214:Capsules; D011108:Polymers; D052203:Ferrosoferric Oxide