Preprint Article Version 1 NOT YET PEER-REVIEWED

Self-Aligned Interdigitated Transducers for Acoustofluidics

Version 1 : Received: 16 November 2016 / Approved: 17 November 2016 / Online: 17 November 2016 (10:28:21 CET)
Version 2 : Received: 22 November 2016 / Approved: 22 November 2016 / Online: 22 November 2016 (09:41:32 CET)

A peer-reviewed article of this Preprint also exists.

Ma, Z.; Teo, A.J.T.; Tan, S.H.; Ai, Y.; Nguyen, N.-T. Self-Aligned Interdigitated Transducers for Acoustofluidics. Micromachines 2016, 7, 216. Ma, Z.; Teo, A.J.T.; Tan, S.H.; Ai, Y.; Nguyen, N.-T. Self-Aligned Interdigitated Transducers for Acoustofluidics. Micromachines 2016, 7, 216.

Journal reference: Micromachines 2016, 7, 216
DOI: 10.3390/mi7120216


Surface acoustic wave (SAW) is effective for the manipulation of fluids and particles in microscale. The current approach of integrating interdigitated transducers (IDTs) for SAW generation into microfluidic channels involves complex and laborious microfabrication steps. These steps often require the full access to clean room facilities and hours to align the transducers to the precise location. This work presents an affordable and innovative method for fabricating SAW-based microfluidic devices without the need of clean room facilities and alignment. The IDTs and microfluidic channels are fabricated in the same process and thus precisely self-aligned in accordance with the device design. With the use of the developed fabrication approach, a few types of different SAW-based microfluidic devices have been fabricated and demonstrated for particle separation and active droplet generation.

Subject Areas

surface acoustic wave; acoustofluidics; microfluidics; interdigitated transducers

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Comment 1
Received: 22 November 2016
Commenter: Jeonghun Nam
The commenter has declared there is no conflict of interests.
Comment: I have a suggestion in regards to the citation. The use of liquid metal and the electrode channel to replace the patterned metal IDTs for acoustic force generation has been already introduced in peer-reviewed journal 'Lab on a Chip' on August, 2016 by Nam and Lim for the first time (Lab Chip, 2016, 16, 3750-3755). In this manuscript, authors showed that a conductive liquid-based IDT can be used for the generation of surface acoustic waves on a piezoelectric substrate, which is a simpler and more cost-effective method than the conventional fabrication method.
Therefore, I think that authors of this manuscript need to cite the previous article;!divAbstract
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Response 1 to Comment 1
Received: 24 November 2016
Commenter: Nam-Trung Nguyen
Commenter's Conflict of Interests: I'm one of the authors of the paper
Comment: We thank the commenter for suggesting the recently published work. However, it appears that the commenter is actually one of the authors for the suggested paper. We acknowledged that your work is relevant to our current manuscript and we will cite the work accordingly. However, we would like to make several clarifications. Firstly, our current work was not inspired by your work as we were not aware of your work previously. This current manuscript was a continuation of what we have demonstrated since 2014. A total of at least 5 of our previous publications have used the approach to fabricate electrodes in microchannel. Our past works are testaments that the proposed method is both reliable and possessed distinct advantages. Second, we would also like to point out that our work is substantially different from your work. In your work, the focus is on the use of your technology in an open system. Manually pipetted droplets were mixed through the induced acoustic streaming. In our current work, we emphasized here on the self-alignment of IDTs with respect to closed microfluidic channels. Using this distinctive feature, we successfully demonstrated that our system can be used to manipulate both droplet generation and particle sorting.
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