Acoustofluidic Droplet Sorter Based on Single Phase Focused Transducers

Abstract

Droplet microfluidics has revolutionized the biomedical and drug development fields by allowing for independent microenvironments to conduct drug screening at the single cell level. However, current microfluidic sorting devices suffer from drawbacks such as high voltage requirements (e.g., >200 Vpp), low biocompatibility, and/or low throughput. In this article, a single‐phase focused transducer (SPFT)‐based acoustofluidic chip is introduced, which outperforms many microfluidic droplet sorting devices through high energy transmission efficiency, high accuracy, and high biocompatibility. The SPFT‐based sorter can be driven with an input power lower than 20 Vpp and maintain a postsorting cell viability of 93.5%. The SPFT sorter can achieve a throughput over 1000 events per second and a sorting purity up to 99.2%. The SPFT sorter is utilized here for the screening of doxorubicin cytotoxicity on cancer and noncancer cells, proving its drug screening capability. Overall, the SPFT droplet sorting device shows great potential for fast, precise, and biocompatible drug screening.

Microfluidic nanodevices for drug sensing and screening applications

“…2 b) ( Schuster et al, 2020 ). Moreover, to reduce the sample volume and improve throughput, droplet-based microfluidic sorters are becoming increasingly popular, and fluorescence detection is widely used to obtain signals for drug identification and screening ( Hu et al, 2020 ; Paek et al, 2019 ; Zhong et al, 2021 ).

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“…The influence of sensing materials; gold nanoparticles, reproduced with permission from ( Kim et al, 2014 ), copyright 2014 Wiley-VCH; graphene, reproduced with permission from ( Song et al, 2022 ), copyright 2022 Wiley-VCH, and DNA, reproduced with permission from ( Nummelin et al, 2018 ), copyright 2018 Wiley-VCH. The influence of surface morphology, reproduced with permission from ( He et al, 2019 ), copyright 2019 Wiley-VCH, and geometrical designs, reproduced with permission from ( Zhong et al, 2021 ), copyright 2021 Wiley-VCH. Drug screening and detection techniques; optical, reproduced with permission from ( Liang et al, 2019 ; Yu et al, 2020 ), copyright 2019, 2020 Wiley-VCH, respectively; electrochemical, reproduced with permission from ( Xu et al, 2021 ), copyright 2021 Wiley-VCH, and mass spectroscopy.…”

A Monolithic 3D Printed Axisymmetric Co-Flow Single and Compound Emulsion Generator

“…Droplet microfluidics has been a powerful tool used in various investigations including single-cell studies in which single-cell assays can be used to produce monoclonal antibodies from individual hybridoma cell clones; the analysis of protein crystal growth and enzyme kinetics; as well as studies of directed evolution by in vitro selection; small-molecule synthesis in microdroplets; and drug discovery [39,40]. Additionally, in-droplet IFN-γ capture assays have recently been studied using droplet encapsulation that could help prevent the diffusion of secreted products to neighboring cells, dramatically reducing both false positives and false negatives relative to assays performed without droplets [14].…”

Sorting of droplets at kHz rates using absorbance activated acoustic sorting

“…Acoustic droplet sorting, has shown to sort droplets and particles at kHz droplet rates. 3,[7][8][9][10][11] The sorting is enabled by acoustic streaming inside a channel changing the flow and deflecting droplets. Acoustic sorting is therefore independent of droplet content, properties or volume and uses lower applied power to achieve sorting.…”

“…Such electric field strengths can potentially harm cells and electroporation or a loss of viability has been reported. 6,7…”