Acoustic trapping of microbubbles in complex environments and controlled payload release
Acoustic trapping of microbubbles in complex environments and controlled payload release
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DOI：
10.1073/pnas.2003569117
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发表时间：
2020-07-07
影响因子：
11.1
通讯作者：
Garbin, Valeria
中科院分区：
文献类型：
--
作者：
Baresch, Diego;Garbin, Valeria
利用声波对微粒进行非接触式操纵，有望在从细胞分选到三维(3D)打印和组织工程的各种应用中发挥作用。然而，声波捕捉在生物医学环境中应用的独特潜力在很大程度上仍未得到开发。特别是，声波诱捕相对于光学诱捕的主要优势，即声音在厚重和不透明的介质中传播的能力，尚未得到充分利用。在这里，我们在实验上演示了使用最近开发的单波束声学镊子技术来捕获微泡，这是一类重要的生物医学相关微粒。我们发现，传输中的涡旋光束的消失压力区可以通过强迫低振幅的非球面形状的振荡来限制微气泡，从而实现其完全的三维定位。我们的解释通过绝对定标的声捕捉力和孤立的气泡回波的直接空间映射来验证，两者都与我们的理论模型很好地吻合。此外，我们通过厘米厚的仿生弹性材料层证明了陷阱的稳定性。最后，我们演示了纳米颗粒负载微泡的同时捕获和独立声场的激活以触发纳米颗粒的释放。总体而言，仅使用声能来定位和驱动微泡，为在受限、难以到达的位置受控输送药物有效载荷铺平了道路，具有潜在的活体应用前景。
Contactless manipulation of microparticles using acoustic waves holds promise for applications ranging from cell sorting to three-dimensional (3D) printing and tissue engineering. However, the unique potential of acoustic trapping to be applied in biomedical settings remains largely untapped. In particular, the main advantage of acoustic trapping over optical trapping, namely the ability of sound to propagate through thick and opaque media, has not yet been exploited in full. Here we demonstrate experimentally the use of the recently developed technique of single-beam acoustical tweezers to trap microbubbles, an important class of biomedically relevant microparticles. We show that the region of vanishing pressure of a propagating vortex beam can confine a microbubble by forcing low-amplitude, nonspherical, shape oscillations, enabling its full 3D positioning. Our interpretation is validated by the absolute calibration of the acoustic trapping force and the direct spatial mapping of isolated bubble echos, for which both find excellent agreement with our theoretical model. Furthermore, we prove the stability of the trap through centimeter-thick layers of bio-mimicking, elastic materials. Finally, we demonstrate the simultaneous trapping of nanoparticle-loaded microbubbles and activation with an independent acoustic field to trigger the release of the nanoparticles. Overall, using exclusively acoustic powering to position and actuate microbubbles paves the way toward controlled delivery of drug payloads in confined, hard-to-reach locations, with potential in vivo applications.