Visualization-enhanced under-oil open microfluidic system for in situ characterization of multi-phase chemical reactions

Qiyuan Chen; Hang Zhai; David J Beebe; Chao Li; Bu Wang

doi:10.1038/s41467-024-45076-7

Visualization-enhanced under-oil open microfluidic system for in situ characterization of multi-phase chemical reactions

Nat Commun. 2024 Feb 7;15(1):1155. doi: 10.1038/s41467-024-45076-7.

Authors

Qiyuan Chen¹, Hang Zhai², David J Beebe^{3

4

5}, Chao Li⁶, Bu Wang^{7

8}

Affiliations

¹ Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA.
² Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA.
³ Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.
⁴ Department of Pathology and Laboratory Medicine, Madison, WI, 53705, USA.
⁵ Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53705, USA.
⁶ Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, 53705, USA. cli479@wisc.edu.
⁷ Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA. bu.wang@wisc.edu.
⁸ Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA. bu.wang@wisc.edu.

Abstract

Under-oil open microfluidic system, utilizing liquid-liquid boundaries for confinements, offers inherent advantages including clogging-free flow channels, flexible access to samples, and adjustable gas permeation, making it well-suited for studying multi-phase chemical reactions that are challenging for closed microfluidics. However, reports on the novel system have primarily focused on device fabrication and functionality demonstrations within biology, leaving their application in broader chemical analysis underexplored. Here, we present a visualization-enhanced under-oil open microfluidic system for in situ characterization of multi-phase chemical reactions with Raman spectroscopy. The enhanced system utilizes a semi-transparent silicon (Si) nanolayer over the substrate to enhance visualization in both inverted and upright microscope setups while reducing Raman noise from the substrate. We validated the system's chemical stability and capability to monitor gas evolution and gas-liquid reactions in situ. The enhanced under-oil open microfluidic system, integrating Raman spectroscopy, offers a robust open-microfluidic platform for label-free molecular sensing and real-time chemical/biochemical process monitoring in multi-phase systems.

Grants and funding

P30 CA014520/CA/NCI NIH HHS/United States