(435c) Stop Flow Lithography: Beyond PDMS Microfluidic Devices

Stop flow lithography has become a powerful technique to functionalize complex functional microparticles [1,2]. Currently, flow lithography relies on the use of polydimethylsiloxane microchannels, because the process requires local inhibition of polymerization, near channel interfaces, via oxygen permeation. The dependence on polydimethylsiloxane devices greatly limits the range of precursor materials that can be processed in flow lithography. Here we present oxygen-free flow lithography via inert fluid-lubrication layers for the synthesis of new classes of complex microparticles [3]. We use an initiated chemical vapour deposition nano-adhesive bonding technique to create non-polydimethylsiloxane-based devices. We successfully synthesize microparticles with a sub-second residence time and demonstrate on-the-fly alteration of particle height. This technique greatly expands the synthesis capabilities of flow lithography, enabling particle synthesis, using water-insoluble monomers, organic solvents, and hydrophobic functional entities such as quantum dots and single-walled carbon nanotubes. As one demonstrative application, we created near-infrared barcoded particles for real-time, label-free detection of target analytes.

1. Dendukuri, D., Gu, S.S., Pregibon, D.C., Hatton, T.A., and Doyle, P.S., "Stop flow lithography in a microfluidic device", Lab on Chip, 7, 818-828, 2007.

2. Dendukuri, D., Pregibon, D.C., Collins, J., Hatton, T.A. and Doyle, P.S. "Continuous Flow Lithography for High-Throughput Microparticle Synthesis", Nature Materials, 5, 365-369, 2006

3. Bong, K.W., Xu, J., Kim, J.-H., Chapin, S.C., Strano, M.S., Gleason, K.K., and Doyle, P.S., "Non-polydimethylsiloxane devices for Oxygen-Free Flow Lithography", Nature Communications, 3, 805 2012.