MRI detectable polymer microspheres embedded with magnetic ferrite nanoclusters for embolization: In vitro and in vivo evaluation

Abstract

Objective: The objective of this study was to develop magnetic embolic microspheres that could be visualized by clinical magnetic resonance imaging (MRI) scanners aiming to improve the efficiency and safety of embolotherapy. Methods and discussion: Magnetic ferrite nanoclusters (FNs) were synthesized with microwave-assisted solvothermal method, and their morphology, particle size, crystalline structure, magnetic properties as well as T2 relaxivity were characterized to confirm the feasibility of FNs as an MRI probe. Magnetic polymer microspheres (FNMs) were then produced by inverse suspension polymerization with FNs embedded inside. The physicochemical and mechanical properties (including morphology, particle size, infrared spectra, elasticity, etc.) of FNMs were investigated, and the magnetic properties and MRI detectable properties of FNMs were also assayed by vibrating sample magnetometer and MRI scanners. Favorable biocompatibility and long-term MRI detectability of FNMs were then studied in mice by subcutaneous injection. FNMs were further used to embolize rabbits’ kidneys to evaluate the embolic property and detectability by MRI. Conclusion: FNMs could serve as a promising MRI-visualized embolic material for embolotherapy in the future.