MAGNETIC MICROBUBBLES, METHODS OF PREPARING THEM AND THEIR USES

摘要

The invention provides a method of preparing a suspension of microbubbles for use in a carrier liquid, wherein the microbubbles have a gas core and a liquid shell, said liquid shell comprising magnetic nanoparticles, and wherein the microbubbles satisfy the following conditions: (i) the force due to buoyancy (FBW) of the microbubble in the carrier liquid is greater than the weight (W) of the microbubble; (ii) the magnetic force (FM) on the microbubble due to a magnetic field applied to the carrier liquid is greater than the combined weight (W) and force due to buoyancy (FBW) of the microbubble; (iii) said magnetic force (FM) on the microbubble is greater than the force due to viscous drag (FD) on the microbubble due to flow of the carrier liquid; and (iv) the scattering cross section (&sgr;scat) of the microbubble to ultrasound allows the microbubble to be detectable and rupturable on exposure to ultrasound.