Affiliation: School of Engineering, Sun Yat-Sen University, Guangzhou 510006, P. R. China.
Microbubbles (MBs) are gas-filled hollow microparticles. Under the ultrasound field, the difference of acoustic characteristics between gas and plasma in the blood vessel will cause strong impedance mismatch and echogenicity to enhance ultrasonic grey scale imaging. The linear or nonlinear resonance of MB shell in the ultrasound field would lead to repeated expansion-contraction till destruction. In this case, the pre-loaded drug in the MB shell will be released in an accelerated manner triggered by the ultrasound at a probe–given site. Sonoporation effect of the cell membrane would also help increase the uptake of substances into cells. This paper is dedicated to review recent developments on MBs, especially multifunctionalized MBs, as a potential drug/gene delivery microdevices for both diagnosis and therapy of malignant tumors.