Single cell technology and endosymbioses
The ability to obtain information at the single-cell level and to perturb individual cells is of central importance for numerous biological questions. There is a growing awareness that individual cells, although genetically identical to sister cells, show different phenotypes and gene expression profiles and therefore different levels of proteins and metabolites. There is also a need to manipulate individual cells to validate hypotheses and to substantiate fundamental biological principles. The analysis of individual cells represents a major challenge, and thus, there is a demand for innovative technologies for cell perturbation as well as sampling, extraction, and high-sensitivity molecular detection.
The recently invented fluidic force microscope (FluidFM) by T. Zambelli and coworkers (ETH Zurich, D-ITET) is an atomic force microscope (AFM) provided with microchanneled cantilevers for local liquid dispensing (Meister et al., 2009 Nano Letters 9:2501–7). The "nanosyringe" is operated on top of an inverted optical microscope, allowing optical inspection during cell manipulation. In an interdisciplinary collaboration with the inventors of the FluidFM and the ETH Spinoff company Cytosurge, we are developing the technology for applications in different complementary areas of single-cell manipulation, including the spatial manipulation, cell adhesion, injection, and extraction of single cells. We established spatial manipulation of viruses, bacteria, yeasts and mammalian cells and are also using the technology to study host-microbe interactions. Single-cell force spectroscopy (SCFS) of individual cells has been demonstrated for bacteria, yeasts and mammalian cells. During this process, the chemical fixation used in conventional SCFS is replaced by sucking the cell to the cantilever opening by underpressure, allowing the generation of independent biological data in a serial fashion within a relatively short period of time. In another line of experiments, we demonstrated the controlled injection of femtoliter volumes into single mammalian cells and dedicated subcompartments, i.e., the nucleus. Among other potential applications, experimental perturbation by nanoinjection with the FluidFM can target the metabolism and other subsystems of the cell's interaction network and has great potential for hypothesis-driven research, which we plan to explore in future projects. Another future application consists in the spatial patterning of bacterial communities at microscale resolution to investigate microbial interactions.
Keywords:
Atomic force microscopy (AFM); Optical microscopy; Hollow cantilevers
Funding:
external pageVolkswagen-Foundation
external pageERC Advanced Grant