Single-cell level array of yeast cells in pumpless microfluidic channels induced by receding meniscus

We present a simple receding meniscus induced method to capture non-adherent yeast cells onto microwells inside microfluidic channels. Microwells were fabricated by capillary molding onto glass substrate using a UV curable polyurethane acrylate (PUA) solution, leading to well-defined, robust microstructures. A cell suspension of the budding yeast, Saccharomyces cerevisiae, was introduced into microfluidic channels by capillary filling and a receding meniscus was subsequently generated by evaporation. As the meniscus receded, yeast cells were spontaneously captured onto microwells at single-cell level. Using this cell-based platform, we observed the response of yeast cells upon stimulation by a mating pheromone (alpha-factor) by monitoring the expression of green fluorescent protein (GFP) with time. It was observed that a-factor triggered the expression of GFP at 60 min after stimulation and the fluorescence intensity was sustained for additional 60 min without changes.