Session: Rising Stars of Mechanical Engineering Celebration & Showcase

Paper Number: 148675

148675 - Additive Manufacturing Acoustofluidic Devices With Spatially Engineered 3d-Fluidics 

Here we introduce an innovative set of strategies, processing approaches, and microfluidic designs for the fabrication of acoustofluidic devices using readily available resin-based three-dimensional (3D) printers. Additive manufacturing (AM) or 3D-printing is emerging as a powerful alternative to traditional planar (2D) fabrication techniques for microfluidic devices. AM offers powerful capabilities for producing structurally complex objects with true 3D architectures through a rapidly expanding library of printing methods. Our work showcases a modular 3D-printed acoustofluidic platform that illustrates several unique aspects of an AM-based approach for developing such devices. In particular, our results underscore the potential of harnessing the 3D design space in acoustofluidics by fabricating fluidic components (micromixers and channels) with intricate channel architectures that facilitate standard acoustofluidic operations, including acoustophoretic particle focusing and fluid micromixing

While AM processes have been widely employed to produce molds for soft lithography, their application to acoustofluidics remains relatively unexplored. Conventional acoustofluidic devices are predominantly formed from silicon or glass substrates through costly, labor-intensive micromachining processes[1][2]. Recent studies have reported the use of conventional manufacturing techniques, such as micro-injection molding or hot embossing [3], to create low-cost polymer acoustofluidic devices. However, these methods can require substantial startup costs, utilize specialized equipment, and lack the flexibility required for swift customization or device optimization.

Our methodology leverages the inherent versatility of AM to facilitate rapid design iterations, enable bespoke designs, and promote the investigation of novel geometries for acoustofluidic operations. We employ micro digital light processing (µDLP) to fabricate prototype devices featuring monolithic channels specifically designed for bulk-wave acoustophoresis and micromixing applications, operating in a manner analogous to silicon-based acoustofluidic devices. We demonstrate that the efficacy of these 3D-printed polymeric devices in supporting acoustophoresis is intimately tied to the geometric thickness of the device. The 3D-printing approach allows us to exploit this relationship to precisely modulate the strength of acoustic focusing by adjusting the device thickness (either top, bottom, or both). Additionally, we exhibit acoustic-streaming induced mixing, a well-established mixing technique in silicon-based acoustofluidic devices [4], by integrating sharp-edged tip features directly within the printed channels. A representative demonstration showcases device performance, where the application of an acoustic field (t = 10 s, flow rate 6 µL/min, 40 Vpp) generates acoustic streaming, resulting in immediate mixing.

3D-printing holds the promise of revolutionizing the rapid prototyping of acoustofluidic devices by drastically reducing fabrication time and cost, while simultaneously expanding the design space for innovative device architectures and functionalities. By enabling true 3D design of microfluidic channels and fluid control components, such as valves, AM methods deployed here facilitate the creation of acoustofluidic device architectures that would typically be unattainable using planar (2D) fabrication techniques enabling new concepts that enhance the capabilities and performance of such devices.

References:

1.     H. N. Açıkgöz, A. Karaman, M. A. Şahin, Ö. R. Çaylan, G. C. Büke, E. Yıldırım, İ. C. Eroğlu, A. E. Erson-Bensan, B. Çetin and M. B. Özer, Ultrasonics, 2023, 129, 106911.

2.     X. Zhao, H. Chen, Y. Xiao, J. Zhang, Y. Qiu, J. Wei and N. Hao, Chemical Engineering Journal, 2022, 447, 137547.

3.     F. Lickert, M. Ohlin, H. Bruus and P. Ohlsson, J. Acoust. Soc. Am., 2021, 149, 4281–4291.

4.     P. H. Huang, Y. Xie, D. Ahmed, J. Rufo, N. Nama, Y. Chen, C. Y. Chan and T. J. Huang, Lab Chip, 2013, 13, 3847.

Presenting Author: Tyler Ray University of Hawaii at Manoa

Presenting Author Biography: Tyler R. Ray is an Assistant Professor of Mechanical Engineering at the University of Hawaii at Manoa. He received a B.S. (2008) and M.S. (2010) in Mechanical Engineering from the University of South Carolina, and a Ph.D. (2015) in Mechanical Engineering from the University of California, Santa Barbara. His research interests are at the intersection of 3D printing functional materials, lab-on-chip diagnostics, and wearable sensing.

Authors: