title: Transverse acoustic trapping using a gaussian focused ultrasound.
abstract: The optical tweezer has become a popular device to manipulate particles in nanometer scales and to study the underlying principles of many cellular or molecular interactions. Theoretical analysis was previously carried out at the authors' laboratory, to show that similar acoustic trapping of microparticles may be possible with a single beam ultrasound. This article experimentally presents the transverse trapping of 125 microm lipid droplets under an acoustically transparent mylar film, which is an intermediate step toward achieving acoustic tweezers in three-dimension. Despite the lack of axial trapping capability in the current experimental arrangement, it was found that a 30 MHz focused beam could be used to laterally direct the droplets toward the focus. The spatial range within which acoustic traps may guide droplet motion was in the range of hundreds of micrometers, much greater than that of optical traps. This suggests that this acoustic device may offer an alternative for manipulating microparticles in a wider spatial range.
authors.affiliation: Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA. jungwool@usc.edu
authors.forename: Jungwoo
authors.initials: J
authors.lastname: Lee
authors.forename: Shia-Yen
authors.initials: SY
authors.lastname: Teh
authors.forename: Abraham
authors.initials: A
authors.lastname: Lee
authors.forename: Hyung Ham
authors.initials: HH
authors.lastname: Kim
authors.forename: Changyang
authors.initials: C
authors.lastname: Lee
authors.forename: K Kirk
authors.initials: KK
authors.lastname: Shung
mesh_terms: D000162:Acoustics; D004867:Equipment Design; D046210:Microfluidic Analytical Techniques; D009038:Motion; D019301:Oleic Acid; D052898:Optical Tweezers; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods*
chemical_list: D019301:Oleic Acid