微通道导引下数字微流体快速混合

Fast Mixing of Digital Droplets Directed by Micro-Channel

微流体混合是微流控芯片急需完善的重要操作单元,提出了在声表面波驱动下实现微通道内数字微流体快速混合方法。在1280YX-LiNbO3基片上设计相互垂直排列的两叉指换能器和反射栅,并在其声传播路径上制作微通道且进行疏水处理以防止微流体偏离运动方向,待混合的数字微流体移液于微通道中,分别在两叉指换能器上分时加RF电信号激发相互垂直声表面波,以驱动微通道中微流体输运、合并及快速混合。输运实验结果表明微流体在没有微通道时运动发生严重偏离声传播方向;混合实验表明:相比于自由扩散混合,声表面波作用极大地提高微通道中微流体混合速度且混合程度更高。

As mixture for droplets is important and needs to be improved in lab-on-a-chip, a fast mixing method for digital droplets in micro-channel driven by surface acoustic wave is proposed. Two normal interdigital transducers and reflector were fabricated on 128°YX-LiNbO3 substrate and micro-channels were made on their acoustic paths to keep droplets move along micro-channels. After droplets for mixing were piped in micro-channel, RF signal was on the two interdigital transducers sequentially to excite surface acoustic wave in order to transport.merge and fast mix the droplets. Transporting and mixing experiments show that movement of droplets would be seriously offset acoustic propagation direction without microchannel and mixing velocity and mixing degree of droplets would be improved greatly under surface acoustic wave compared to free diffusion.