Ultrasound Induced Fluorescence of Nanoscale Liposome Contrast Agents.
Ultrasound Induced Fluorescence of Nanoscale Liposome Contrast Agents.
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DOI：
10.1371/journal.pone.0159742
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Mather ML
中科院分区：
文献类型：
--
作者：
Zhang Q;Morgan SP;O'Shea P;Mather ML
据报道，一种新的成像造影剂在应用超声(US)时提供了增强的荧光信号。用光激发的方法，在无超声场和有超声场存在的情况下，利用声荧光装置检测了含有标记为Py的脂类的准分子荧光发射强度。比较了脂肪酸尾基团(PYPC)和头基团(PYPE)上标记了芘的脂质体的声荧光动力学。在两个被研究的病例中，都观察到了暴露于US后准分子发射强度的增加。增加的强度和时间常数被发现对于PYPE和PPC系统是不同的，并且依赖于施加的US压力和曝光时间。PYPC标记脂质体的荧光强度变化最大(130%)，上升时间常数最小(0.33 S)。PYPC标记脂质体中准分子发射强度增加的机制被认为是由于酰基链的“摆动”引起的，这种“摆动”涉及快速响应和较低的US压力。伴随而来的是较高超声压力下脂质侧向扩散率的增加，这一机制在PYPE标记的脂质体中也是活跃的。
A new imaging contrast agent is reported that provides an increased fluorescent signal upon application of ultrasound (US). Liposomes containing lipids labelled with pyrene were optically excited and the excimer fluorescence emission intensity was detected in the absence and presence of an ultrasound field using an acousto-fluorescence setup. The acousto-fluorescence dynamics of liposomes containing lipids with pyrene labelled on the fatty acid tail group (PyPC) and the head group (PyPE) were compared. An increase in excimer emission intensity following exposure to US was observed for both cases studied. The increased intensity and time constants were found to be different for the PyPC and PyPE systems, and dependent on the applied US pressure and exposure time. The greatest change in fluorescence intensity (130%) and smallest rise time constant (0.33 s) are achieved through the use of PyPC labelled liposomes. The mechanism underlying the observed increase of the excimer emission intensity in PyPC labelled liposomes is proposed to arise from the “wagging” of acyl chains which involves fast response and requires lower US pressure. This is accompanied by increased lipid lateral diffusivity at higher ultrasound pressures, a mechanism that is also active in the PyPE labelled liposomes.