Capture & Release of Single Cells on a Microfluidic Chip Via Conical Nanopores

In modern biology, it is often assumed that populations of cells are composed primarily of average cells; cells that do not deviate significantly from an observational mean. This assumption is empirically convenient and until recently was necessary due to technological limitations. However, it is possible that ignorance of cellular individuality may lead one to draw incorrect conclusions, especially when the population under study is heterogeneous. Cells that exhibit significant deviation from the mean behavior can reveal important information which would be normally obscured by ensemble averaging techniques.We have developed an array of microfluidic analytical techniques capable of studying the biochemistry of single cells [1,2,3]. Our current effort focuses on the development of a device which can capture a significantly large number of unicellular organisms resolved at the single-cell level. In our microchip, Synechococcus cells are captured via electroosmostic flow on a thin polycarbonate membrane that is populated by conical nanopores [4]. Cells can be efficiently captured and released via control of the flow's directionality. Applications of this chip, including those for high-throughput selective sorting and on-chip culturing, are being explored.1. Wheeler, A. R., Throndset, W. R., Zare, R. N. et al. Anal Chem75, 3581-3586 (2003).2. Wu, H., Wheeler, A. & Zare, R. N. Proc Natl Acad Sci U S A101, 12809-12813 (2004).3. Huang, B., Wu, H., Zare, R. N. et al. Science315, 81-84 (2007).4. Scopece, P., Ugo, P., Martin, C. et al. Nanotech.17, 3951-3956 (2006).