Liu Hsiao-Chuan, Li Ying, Chen Ruimin, Jung Hayong, Shung K Kirk
Department of Biomedical Engineering and NIH Ultrasonic Transducer Resource Center, University of Southern California, Los Angeles, California, USA; Hematology and Oncology, Children's Hospital Los Angeles, Los Angeles, California, USA.
Department of Biomedical Engineering and NIH Ultrasonic Transducer Resource Center, University of Southern California, Los Angeles, California, USA.
Ultrasound Med Biol. 2017 Apr;43(4):852-859. doi: 10.1016/j.ultrasmedbio.2016.12.005. Epub 2017 Feb 22.
Single-beam acoustic tweezers (SBATs) represent a new technology for particle and cell trapping. The advantages of SBATs are their deep penetration into tissues, reduction of tissue damage and ease of application to in vivo studies. The use of these tools for applications in drug delivery in vivo must meet the following conditions: large penetration depth, strong trapping force and tissue safety. A reasonable penetration depth for SBATs in the development of in vivo applications was established in a previous study conducted in water with zero velocity. However, capturing objects in flowing fluid can provide more meaningful results. In this study, we investigated the capability of SBATs to trap red blood cells (RBCs) and polystyrene microspheres in flowing RBC suspensions. Two different types of RBC suspension were prepared in this work: an RBC phosphate-buffered saline (PBS) suspension and an RBC plasma suspension. The results indicated that SBATs successfully trapped RBCs and polystyrene microspheres in a flowing RBC PBS suspension with an average steady velocity of 1.6 cm/s in a 2-mm-diameter polyimide. Furthermore, SBATs were found able to trap RBCs in a flowing RBC PBS suspension at speeds as high as 7.9 cm/s in a polyimide tube, which is higher than the velocity in capillaries (0.03 cm/s) and approaches the velocity in arterioles and venules. Moreover, the results also indicated that polystyrene microspheres can be trapped in an RBC plasma suspension, where aggregation is observed. This work represents a step forward in using this tool in actual in vivo experimentation.
单束声镊（SBATs）是一种用于捕获粒子和细胞的新技术。SBATs的优点在于其能够深入组织、减少组织损伤并且易于应用于体内研究。将这些工具用于体内药物递送应用必须满足以下条件：穿透深度大、捕获力强以及组织安全性高。在先前一项在零流速的水中进行的研究中，确定了SBATs在体内应用开发中的合理穿透深度。然而，在流动流体中捕获物体可以提供更有意义的结果。在本研究中，我们研究了SBATs在流动的红细胞（RBC）悬浮液中捕获红细胞和聚苯乙烯微球的能力。在这项工作中制备了两种不同类型的RBC悬浮液：RBC磷酸盐缓冲盐水（PBS）悬浮液和RBC血浆悬浮液。结果表明，SBATs在直径为2毫米的聚酰亚胺管中，以1.6厘米/秒的平均稳定流速成功地在流动的RBC PBS悬浮液中捕获了红细胞和聚苯乙烯微球。此外，发现在聚酰亚胺管中，SBATs能够在高达7.9厘米/秒的流速下在流动的RBC PBS悬浮液中捕获红细胞，这一速度高于毛细血管中的速度（0.03厘米/秒），并接近小动脉和小静脉中的速度。此外，结果还表明聚苯乙烯微球可以在观察到聚集现象的RBC血浆悬浮液中被捕获。这项工作代表了在实际体内实验中使用该工具方面向前迈出的一步。
