Department of Imaging Sciences, Imperial College London, London, United Kingdom.
Ultrasound Med Biol. 2012 May;38(5):864-75. doi: 10.1016/j.ultrasmedbio.2012.01.027.
In addition to improving image contrast, microbubbles have shown great potential in molecular imaging and drug/gene delivery. Previous work by the authors showed that considerable improvements in gene transfection efficiency were obtained using microbubbles loaded with magnetic nanoparticles under simultaneous exposure to ultrasound and magnetic fields. The aim of this study was to characterise the effect of nanoparticles on the dynamic and acoustic response of the microbubbles. High-speed video microscopy indicated that the amplitude of oscillation was very similar for magnetic and nonmagnetic microbubbles of the same size for the same ultrasound exposure (0.5 MHz, 100 kPa, 12-cycle pulse) and that this was minimally affected by an imposed magnetic field. The linear scattering to attenuation ratio (STAR) was also similar for suspensions of both bubble types although the nonlinear STAR was ~50% lower for the magnetic microbubbles. Both the video and acoustic data were supported by the results from theoretical modelling.
除了提高图像对比度外，微泡在分子成像和药物/基因传递方面也显示出巨大的潜力。作者之前的工作表明，在同时暴露于超声和磁场的情况下，负载磁性纳米颗粒的微泡可显著提高基因转染效率。本研究的目的是研究纳米颗粒对微泡动力学和声学响应的影响。高速视频显微镜表明，在相同的超声暴露（0.5MHz、100kPa、12 个周期脉冲）下，相同尺寸的磁性和非磁性微泡的振荡幅度非常相似，而磁场的施加对其影响很小。两种类型气泡悬浮液的线性散射衰减比（STAR）也相似，尽管磁性微泡的非线性 STAR 低约 50%。视频和声学数据均得到理论模型结果的支持。
