title: Single-Beam Acoustic Trapping of Red Blood Cells and Polystyrene Microspheres in Flowing Red Blood Cell Saline and Plasma Suspensions.
abstract: 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.
authors.affiliation: 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.
authors.forename: Hsiao-Chuan
authors.initials: HC
authors.lastname: Liu
authors.affiliation: Department of Biomedical Engineering and NIH Ultrasonic Transducer Resource Center, University of Southern California, Los Angeles, California, USA. Electronic address: yli582@usc.edu.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Biomedical Engineering and NIH Ultrasonic Transducer Resource Center, University of Southern California, Los Angeles, California, USA.
authors.forename: Ruimin
authors.initials: R
authors.lastname: Chen
authors.affiliation: Department of Biomedical Engineering and NIH Ultrasonic Transducer Resource Center, University of Southern California, Los Angeles, California, USA.
authors.forename: Hayong
authors.initials: H
authors.lastname: Jung
authors.affiliation: Department of Biomedical Engineering and NIH Ultrasonic Transducer Resource Center, University of Southern California, Los Angeles, California, USA. Electronic address: kkshung@usc.edu.
authors.forename: K Kirk
authors.initials: KK
authors.lastname: Shung
mesh_terms: D000162:Acoustics; D000465:Algorithms; D000818:Animals; D001011:Aorta; D001783:Blood Flow Velocity; D004912:Erythrocytes; D051379:Mice; D008846:Micromanipulation / Q000295:instrumentation / Q000379:methods*; D008863:Microspheres; D011137:Polystyrenes; D012965:Sodium Chloride; D013535:Suspensions; D013552:Swine; D014159:Transducers; D000069453:Ultrasonic Waves
chemical_list: D011137:Polystyrenes; D013535:Suspensions; D012965:Sodium Chloride
keywords: Acoustic tweezer; Plasma; Plasma suspension; Polystyrene microspheres; Red blood cells; Single-beam acoustic trapping; Ultrasound