Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0192, Japan.
School of Engineering, Macquarie University, Sydney 2122, Australia.
Biosensors (Basel). 2021 Aug 4;11(8):263. doi: 10.3390/bios11080263.
Continuous microfluidic focusing of particles, both synthetic and biological, is significant for a wide range of applications in industry, biology and biomedicine. In this study, we demonstrate the focusing of particles in a microchannel embedded with glass grooves engraved by femtosecond pulse (fs) laser. Results showed that the laser-engraved microstructures were capable of directing polystyrene particles and mouse myoblast cells (C2C12) towards the center of the microchannel at low Reynolds numbers (Re < 1). Numerical simulation revealed that localized side-to-center secondary flows induced by grooves at the channel bottom play an essential role in particle lateral displacement. Additionally, the focusing performance proved to be dependent on the angle of grooves and the middle open space between the grooves based on both experiments and simulation. Particle sedimentation rate was found to critically influence the focusing of particles of different sizes. Taking advantage of the size-dependent particle lateral displacement, selective focusing of micrometer particles was demonstrated. This study systematically investigated continuous particle focusing in a groove-embedded microchannel. We expect that this device will be used for further applications, such as cell sensing and nanoparticle separation in biological and biomedical areas.
连续微流控聚焦颗粒，无论是合成的还是生物的，在工业、生物学和生物医学的广泛应用中都具有重要意义。在这项研究中，我们展示了在嵌入有飞秒激光（fs）雕刻玻璃槽的微通道中对颗粒的聚焦。结果表明，激光雕刻的微结构能够在低雷诺数（Re<1）下将聚苯乙烯颗粒和小鼠成肌细胞（C2C12）引导至微通道的中心。数值模拟表明，通道底部凹槽引起的局部侧向向心二次流在颗粒侧向位移中起着重要作用。此外，实验和模拟都表明，聚焦性能取决于凹槽的角度和凹槽之间的中间开放空间。发现颗粒沉降速度对不同尺寸颗粒的聚焦有很大影响。利用颗粒侧向位移的尺寸依赖性，实现了微米颗粒的选择性聚焦。这项研究系统地研究了嵌入式微通道中连续的颗粒聚焦。我们期望该装置将用于进一步的应用，如生物和生物医学领域的细胞传感和纳米颗粒分离。
