Cryo-printed microfluidics enable rapid prototyping for optical-cell analysis

Abstract

This paper highlights an innovative, low-cost rapid-prototyping method for generating microfluidic chips with extraordinary short fabrication times of only a few minutes. Microchannels and inlet/outlet ports are created by controlled deposition of aqueous microdroplets on a cooled surface resulting in printed ice microstructures, which are in turn coated with a UV-curable acrylic cover layer. Thawing leaves an inverse imprint as a microchannel structure. For an exemplary case, we applied this technology for creating a microfluidic chip for cell-customized optical-cell analysis. The chip design includes containers for cell cultivation and analysis. Container shape, length, position, and angle relative to the main channel were iteratively optimized to cultivate and analyze different cell types. With the chip, we performed physiological analyses of morphologically distinct prokaryotic Corynebacterium glutamicum DM1919, eukaryotic Hansenula polymorpha RB11 MOX-GFP, and phototrophic Synechocystis sp. PCC 6803 cells via quantitative time-lapse fluorescence microscopy. The technology is not limited to rapid prototyping of complex biocompatible microfluidics. Further exploration may include printing with different materials other than water, printing on other substrates in-situ biofunctionalization, the inclusion of electrodes and many other applications.