Abstract:
Dual-modal contrast agent microbubbles (MBs), which can integrate both ultrasound (US) and magnetic resonance imaging (MRI) diagnostic/therapeutic functions, have attracted broad interests of researchers. In the present work, super paramagnetic iron oxide nanoparticles(SPIOs) were embedded into albumin-shelled microbubbles to fabricate dual-modal US/MRI contrast agents (named as SPIO-albumin MBs). Then, the dynamic behaviors of SPIO-albumin MBs, especially the impact of SPIO particle concentration on the inertial cavitation (IC) and thermal effects of SPIO-albumin MBs, were studied based passive cavitation detection (PCD) and thermal couple detecting systems. The results showed that: with constant SPIO concentration, constant, the IC threshold of SPIO-albumin MBs was reduced, as the acoustic driving pulse length increased or the acoustic driving frequency became closer to the MB resonance frequency; the IC dose (ICD) of SPIO-albumin MBs was significantly enhanced with the increasing SPIO concentration; and comparing with pure phosphate buffer saline (PBS) and SPIO solutions, the SPIO-albumin MB solution with more SPIOs embedded into the albumin shell demonstrated greater temperature elevation rate and higher maximum temperature enhancement, which could be helpful to achieve better treatment effect of ultrasound thermal therapy.
