We present a simple, versatile method for the in-situ fabrication of membranes inside a microfluidic channel during a chip manufacturing process using only two extra slanted angle holographic exposure steps. This method combines the strengths of both inclined UV exposure and holographic lithography to produce micrometer-sized three-dimensional sieving structures. Using a common chip material, the photoresist material SU-8, together with this method, a leak-free membrane-channel connection is obtained. The resulting membranes are monodisperse, with a very well-defined pore geometry (i.e., microsieves with a pore diameter between 500 nm and 10 μm) that is easily controllable with the holographic set-up. The selectivity of in-situ fabricated microsieves with a pore diameter of 2 μm will be demonstrated using polystyrene beads of 1 and 3 μm.
- In-situ fabrication
- Inclined lithography
Prenen, A. M., Knopf, A., Bastiaansen, C. W. M., & Broer, D. J. (2011). In-situ fabrication of polymer microsieves for mu TAS by slanted angle holography. Microfluidics and Nanofluidics, 10(6), 1299-1304. https://doi.org/10.1007/s10404-010-0763-4