Because of cellular heterogeneity, the analysis of endogenous molecules from single cells is of significant interest and has major implications. While micromanipulation or cell sorting followed by cell lysis is already used for subsequent molecular examinations, approaches to directly extract the content of living cells remain a challenging but promising alternative to achieving non-destructive sampling and cell-context preservation. Here, we demonstrate the quantitative extraction from single cells with spatiotemporal control using fluidic force microscopy. We further present a comprehensive analysis of the soluble molecules withdrawn from the cytoplasm or the nucleus, including the detection of enzyme activities and transcript abundances. This approach has uncovered the ability of cells to withstand extraction of up to several picoliters and opens opportunities to study cellular dynamics and cell-cell communication under physiological conditions at the single-cell level.

No abstract

Cell adhesion to surfaces represents the basis for niche colonization and survival. Here we establish serial quantification of adhesion forces of different cell types using a single probe. The pace of single-cell force-spectroscopy was accelerated to up to 200 yeast and 20 mammalian cells per probe when replacing the conventional cell trapping cantilever chemistry of atomic force microscopy by underpressure immobilization with fluidic force microscopy (FluidFM). In consequence, statistically relevant data could be recorded in a rapid manner, the spectrum of examinable cells was enlarged, and the cell physiology preserved until approached for force spectroscopy. Adhesion forces of Candida albicans increased from below 4 up to 16 nN at 37°C on hydrophobic surfaces, whereas a Δhgc1-mutant showed forces consistently below 4 nN. Monitoring adhesion of mammalian cells revealed mean adhesion forces of 600 nN of HeLa cells on fibronectin and were one order of magnitude higher than those observed for HEK cells.

A novel method for non‐invasive cell sheet recovery based on polyelectrolyte thin films is presented. Coatings with highly tunable properties allow for controlling the cell surface interactions or can be used as electronically switchable sacrificial layer offering a promising new tool for cell sheet based tissue engineering.