The invention discloses a
polymer magnetic particle composite
ultrasonic imaging microsphere. The
microsphere has a hollow inorganic / organic / inorganic three-layer structure, wherein a cavity is formed in the center of the
microsphere and is filled with air inside; Fe3O4 magnetic particles are formed on the outer layer of the cavity; an intermediate layer is formed by a core / shell
polymer nano microsphere obtained through free radical copolymerization of a poly(
isopropyl acrylamide)-polymethylacrylic acid random
copolymer, polymethylacrylic acid and
divinyl benzene; coordinate bonds or ionic bonds can be formed between the
copolymer and the Fe3O4 magnetic particles on the inner layer of the
copolymer via carboxyl on the inner surface of the microsphere and iron salt, so that the microsphere is stable; an outer layer is formed by
silicon dioxide and is connected with the intermediate layer through
hydrogen-bond intersection between carboxyl on the surface of the microsphere and
silicon hydroxyl on the surface of
silicon dioxide. The material has the advantages that the
polymer microsphere belongs to nanoparticles; a contrast agent can achieve targeted localization via the Fe3O4 magnetic particles on the inner layer; the
silicon dioxide hollow microsphere has good
biocompatibility and
mechanical stability, and the inside cavity can generate strong echo signals in a contrast mode.