Department of Materials Science & Engineering, Chungnam National University, Gungdong, Daejeon, 305-764, South Korea.
Biomed Microdevices. 2012 Dec;14(6):1077-84. doi: 10.1007/s10544-012-9703-2.
In this work, we demonstrated the alignment of polystyrene latex microspheres (diameter of 1 ~45 μm), bio-functionalized superparamagnetic beads (diameter 2.8 μm), and live cells (average diameter 1 ~2 μm) using an ultrasonic standing wave (USW) in a PDMS microfluidic channel (330 μm width) attached on a Si substrate for bio-medical applications. To generate a standing wave inside the channel, ultrasound of 2.25 MHz resonance frequency (for the channel width) was applied by two ultrasound transducers installed at both sides of the channel which caused the radiation force to concentrate the micro-particles at the single pressure nodal plane of USW. By increasing the frequency to the next resonance condition of the channel, the particles were concentrated in dual nodal planes. Migration time of the micro-particles towards the single nodal plane was recorded as 108 s, 17 s, and 115 s for polystyrene particles of 2 μm diameter, bio-functionalized magnetic beads, and live cells, respectively. These successful alignments of the bio-functionalized magnetic beads along the desired part of the channel can enhance the performance of a sensor which is applicable for the bio-hybrid system and the alignment of live cells without any damage can be used for sample pre-treatment for the application of lab-on-a-chip type bioassays.
在这项工作中，我们展示了使用驻超声（USW）在 PDMS 微流道（330μm 宽）中对齐聚苯乙烯乳胶微球（直径 145μm）、生物功能化超顺磁珠（直径 2.8μm）和活细胞（平均直径 12μm），该微流道附着在 Si 衬底上，用于生物医学应用。为了在通道内产生驻波，通过安装在通道两侧的两个超声换能器施加 2.25MHz 共振频率（针对通道宽度）的超声波，这导致辐射力将微颗粒集中在 USW 的单个压力节点平面上。通过将频率增加到通道的下一个共振条件，颗粒集中在双节点平面上。对于 2μm 直径的聚苯乙烯颗粒、生物功能化磁性珠和活细胞，微颗粒朝着单个节点平面的迁移时间分别记录为 108s、17s 和 115s。沿着通道的期望部分对生物功能化磁性珠的成功对齐可以增强传感器的性能，该传感器适用于生物混合系统，并且可以对活细胞进行无任何损伤的对齐，用于微流控芯片类型生物测定应用的样品预处理。
