Department of Medical Biotechnology, College of Life Science and Biotechnology, Dongguk University-Seoul, Seoul, 100-715, Republic of Korea.
Biomed Microdevices. 2011 Aug;13(4):779-88. doi: 10.1007/s10544-011-9548-0.
A high frequency sound beam was employed to explore an experimental method that could control particle motions in a microfluidic device. A 24 MHz single element lead zirconate titanate (PZT) transducer was built to transmit a focused ultrasound of variable duty factors (pulse duration/pulse repetition time), and its 1-3 piezocomposite structure established a tight focusing with f-number (focal depth/aperture size) of one. The transducer was excited by the Chebyshev windowed chirp signal sweeping from 18 MHz to 30 MHz with a 50% of duty factor, in order to ensure that enough sound beams were penetrated into the microfluidic device. The device was fabricated from a polydimethylsiloxane (PDMS) mold, and had a main channel composed of three subchannels among which particles flowed in the middle. A 60~70 μm diameter single droplet in the flow could be trapped near the channel bifurcation, and subsequently diverted into the sheath flow by releasing or shifting the acoustic trap. Hence, the results showed the potential use of a focused sound beam in microfluidic devices, and further suggested that this method could be exploited in the development of ultrasound-based flow cytometry and cell sorting devices.
采用高频声束探索一种能够控制微流控装置中粒子运动的实验方法。构建了一个 24MHz 的单元件锆钛酸铅(PZT)换能器来传输可变占空比（脉冲持续时间/脉冲重复时间）的聚焦超声，其 1-3 型压电器件复合材料结构建立了紧聚焦，其 f 数（焦深/孔径尺寸）为 1。换能器由切比雪夫加窗线性调频信号激励，从 18MHz 扫频到 30MHz，占空比为 50%，以确保足够的声束穿透微流控装置。该装置由聚二甲基硅氧烷（PDMS）模具制成，具有由三个子通道组成的主通道，其中粒子在中间的子通道中流动。在流中可以捕获 60~70μm 直径的单个液滴，并通过释放或移动声阱将其引导到鞘流中。因此，结果表明聚焦声束在微流控装置中的潜在用途，并进一步表明该方法可用于开发基于超声的流式细胞术和细胞分选装置。
