Ferrite plating on porous silica microspheres for ultrasonic contrast agents

Author

Zhang, Minjuan ; Zhang, Qun ; Itoh, Tomoyuki ; Abe, Masanori

Author_Institution

Dept. of Phys. Electron., Tokyo Inst. of Technol., Japan

Volume

30

Issue

6

fYear

1994

fDate

11/1/1994 12:00:00 AM

Firstpage

4692

Lastpage

4694

Abstract

Porous silica microspheres, 1-3 μm in diameter, were coated with Fe₃O₄ by “reactor method” ferrite plating. The polycrystalline Fe₃O₄ coating was synthesized from an aqueous solution (pH=7.3) of FeCl₂ at 60-70°C, using oxidizing solution of NaNO₂ mixed with CH ₃COONH₄ (pH buffer). The magnetite capsulated silica microspheres can be potentially used for contrast agents for clinical ultrasonography, especially for blood flowmetry; the air trapped in the silica pores enhances the ultrasound echogenicity. The contrast agents are controllable by magnetic fields, and their virtual density can be adjusted to that of ambient fluid by changing the thickness of the Fe₃O₄ coating

Keywords

biomedical ultrasonics; ferrites; magnetic particles; magnetic thin films; materials preparation; silicon compounds; 1 to 3 mum; 60 to 70 C; Fe₃O₄; FeCl₂; NaNO₂; blood flowmetry; clinical ultrasonography; ferrite plating; magnetite capsulated silica microspheres; porous silica microspheres; reactor method ferrite plating; ultrasonic contrast agents; ultrasound echogenicity; Blood; Coatings; Ferrites; Fluid flow control; Iron; Magnetic fields; Silicon compounds; Thickness control; Ultrasonic imaging; Ultrasonography;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.334191

Filename

334191