Abstract
Optofluidics, which integrates microfluidics and micro-optical components, is crucial for optical sensing, fluorescence analysis, and cell detection. However, the realization of an integrated system from optofluidic manipulation and a microfluidic channel is often hampered by the lack of a universal substrate for achieving monolithic integration. In this study, we report on an integrated optofluidic-microfluidic twin channels chip fabricated by one-time exposure photolithography, in which the twin microchannels on both surfaces of the substrate were exactly aligned in the vertical direction. The twin microchannels can be controlled independently, meaning that fluids could flow through both microchannels simultaneously without interfering with each other. As representative examples, a tunable hydrogel microlens was integrated into the optofluidic channel by femtosecond laser direct writing, which responds to the salt solution concentration and could be used to detect the microstructure at different depths. The integration of such optofluidic and microfluidic channels provides an opportunity to apply optofluidic detection practically and may lead to great promise for the integration and miniaturization of Lab-on-a-Chip systems.
Highlights
Matter precisely, Yang et al reported on the optofluidic trapping and transport of 75-nm dielectric nanoparticles and λ -DNA molecules using subwavelength liquid-core slot waveguides[22]
In the present microfluidic channel system, the dominant technology of optical micro-detection and analysis is the introduction of fabricated micro-optical components rather than optofluidic devices, which adjust the optical properties of optical elements by controlling fluids[23,24]
The realization of an integrated system from optofluidic manipulation and a microfluidic channel is often hampered by the lack of a universal substrate for achieving monolithic integration
Summary
A one-time exposure method was used here to fabricate the twin optofluidic and microfluidic channels (Fig. 1a). When the supporting environment was changed to water or a CaCl2 water-ethanol solution, the focal length of the microlens became larger than 278 μ m, and the distance between the microlens and the lower surface of the microchannel was 200 μ m; no projection image was observed. The present work demonstrated that the twin optofluidic and microfluidic channels integrated in one chip have been fabricated successfully in the vertical direction of the substrate with exact alignment via one-time exposure photolithography. We believe that this method will be applied to broader applications in the functionalization and miniaturization of Lab-on-a-Chip systems
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