Single-Cell Systems

Transparent microfluidic single-cell culture systems that enable manipulation, cultivation, and on-site release of selected individual cells are fabricated in a simple hybrid glass-photoresist (external page SU-8)-polymer (external page PDMS) approach. Single cells are trapped in a microfluidic channel by using mild suction at cell immobilization orifices, where the cells can be cultivated under controlled environmental conditions or be subjected to on-site analysis.

Enlarged view: Single-Cell Manipulation & Cultivation on Chip
Single-Cell Manipulation & Cultivation on Chip: The yellow layer consists of SU-8, red denotes Pt electrodes, grey the glass substrate.

Cells of interest can be individually and independently released for further downstream treatment by applying negative dielectrophoretic forces via the microelectrodes at each immobilization site. The combination of hydrodynamic cell-trapping and dielectrophoretic methods for cell release enables highly versatile single-cell manipulation in an array-based format.

Budding Yeast Cell at Orifice
Budding Yeast Cell at Orifice: Time-lapse movie; the original duration of the budding process is approximately 70 minutes.
N-DEP effect
Cell release from immobilization orifices through using the "negative dielectrophoretic" effect (nDEP)

Elucidation of cell-to-cell variability and associated hereditary transmission are an important aspect in current research on single-cell analysis. In order to investigate the reasons for cell-to-cell variability – for example, stochastic noise in gene expression, cell aging, or differences in microenvironments – experimental setups are required that enable to monitor cells and their progeny at single-cell resolution over their whole life span.

Enlarged view: Microfluidic Chip for Cell Imaging
Microfluidic Chip for Cell Imaging: Schematic Cross section (left) and top view (right); PDMS has been bonded to a thin glass substrate; continuous medium perfusion is realized through microfluidic pumps.

We are developing microfluidic chips that feature simple but robust operation and cell loading for live-cell imaging of bacteria, yeast and mammalian cells. Cell growth is constrained to a horizontal plane, which enables high-resolution time-lapse imaging using automated microscope control and image acquisition.

Growth of yeast in microfluidic chip
Growth of Yeast in Microfluidic Chip: Time lapse movie of yeast cells cultured under continuous perfusion for 24 hours; fluorescence markers for budneck formation (Myo1) appear at the end of a growth cycle.

Collaborations

Groups at ETH Zurich, Switzerland.

Recent publications

Z. Zhu, Y. Wang, R. Peng, P. Chen, Y. Geng, B. He, S. Ouyang, K.Zheng, Y. Fan, D. Pan, N. Jin, F. Rudolf, A. Hierlemann, "A microfluidic single-​cell array for in situ laminar-​flow-based comparative culturing of budding yeast cells", Talanta 2021, in press (DOI: 10.1016/j.talanta.2021.122401). external page Online

K. Chawla, S Bürgel, G. Schmidt, H-M. Kaltenbach, F. Rudolf, O. Frey, Andreas Hierlemann, "Integrating impedance-based growth-rate monitoring into a microfluidic cell culture platform for live-cell microscopy", Microsystems & Nanoengineering 2018, 4:8 (DOI 10.1038/s41378-018-0006-5). external page Online

M. Modena, K. Chawla, P. Misun, A. Hierlemann, "Smart cell-culture systems: Integration of sensors and actuators into microphysiological systems", ACS Chem. Biol. 2018, 13 (7), pp 1767–1784 (DOI: 10.1021/acschembio.7b01029). external page Online

N. Haandbaek, S. C. Bürgel, F. Rudolf, F. Heer, and A. Hierlemann, "Characterization of single yeast cell phenotypes using microfluidic impedance cytometry and optical imaging", ACS Sensors 2016, 1 (8), pp 1020–1027 (DOI: 10.1021/acssensors.6b00286). external page Online

B. Sorce, C. Escobedo, Y. Toyoda, M. Stewart, C. Cattin, R. Newton, I. Banerjee, A. Stettler, B. Roska, S. Eaton, A. Hyman, A. Hierlemann, D. J. Müller, "Mitotic cells contract actomyosin cortex and generate pressure to round against or escape epithelial confinement", Nature Commununications, 2015, 6:8872 (DOI: 10.1038/ncomms9872). external page Online

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