Abstract
Ultrasound radiation force (USRF) is commonly used to facilitate theefficiency of targeted bubble adhesion. Studying the property of adherentbubbles provides opportunities for the further control of targeted drug deliveryand release. Previous reports show that USRF provides better targetingefficiency as USRF transmitting frequency close to bubbles' resonance frequency.However, low-frequency ultrasound suffers from a large sample volume such thatUSRF cannot be pinpointed to a specified region of interest. In this study, weproposed a high-frequency dual-frequency (DF) excitation with a low-frequencyenvelope component close to bubbles' resonance frequency to enhance the bubblestargeting efficiency while retaining a high spatial resolution. The results showthat dual-frequency excitation with envelope frequency of 20 MHz (DF-20) and 30MHz (DF-30) nearing the resonance frequency of submicron bubbles providedtargeting enhancement up to 4.6-6.2 folds within 2 minutes. In comparisons toDF-3 and DF-10 excitations, which corresponding envelope frequencies were farfrom the resonance frequency of submicron bubbles, perform only 2.7-3.3 foldsenhancement within 5 minutes. © 2010 IEEE.