Abstract
A straightforward method for microfluidic devices fabrication using sunlight as the ultraviolet (UV) source is established in this work. This method is based on photolithography, but obviates the need for specialized UV exposure facility. Substrates coated with photoresist were placed directly under sun in a perpendicular direction to the sunlight for exposure. Exposure conditions were optimized for patterning features with different kinds of photoresist, photoresist of different thicknesses and dimensions. Exposure time can be adjusted to obtain designed features on a mask with good lateral structure according to the energy measured by UV meter (with a constant intensity of UV in sunlight). Masters produced under optimum exposure conditions were used for the fabrication of several microfluidic devices with different materials, structures, or functions. Resultant devices were shown eminently suitable for microfluidic applications such as electrophoretic separation, multiple gradient generator, and pneumatic valve-based cell culture. This photolithographic method is simple, low cost, easy to operate, and environmental friendly. Especially, the masters can be obtained in parallel simultaneously, which is suitable for chip fabrication for mass production. It is also more attractive for the laboratories, in which the support for photolithographic facility is not available.
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Acknowledgments
This research was supported by the NSFC of China (no. 20635030 and 90713014), 863 program (2006AA020201), 973 program, (no. 2007CB714505 and 2007CB714507), The 11st Five Years Key Programs for Science and Technology Development of China (no. 2006BAD12B03-01). The authors also thank Yanfeng Li for helpful discussion.
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Ma, J., Jiang, L., Pan, X. et al. A simple photolithography method for microfluidic device fabrication using sunlight as UV source. Microfluid Nanofluid 9, 1247–1252 (2010). https://doi.org/10.1007/s10404-010-0630-3
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DOI: https://doi.org/10.1007/s10404-010-0630-3