Force-controlled spatial manipulation of viable mammalian cells and micro-organisms by means of FluidFM technology

Abstract

The FluidFM technology uses microchanneled atomic force microscope cantilevers that are fixed to a drilled atomic force microscope cantilevers probeholder. A continuous fluidic circuit is thereby achieved extending from an external liquid reservoir, through the probeholder and the hollow cantilever to the tip aperture. In this way, both overpressure and an underpressure can be applied to the liquid reservoir and hence to the built-in fluidic circuit. We describe in this letter how standard atomic force microscopy in combination with regulated pressure differences inside the microchanneled cantilevers can be used to displace living organisms with micrometric precision in a nondestructive way. The protocol is applicable to both eukaryotic and prokaryotic cells (e.g., mammalian cells, yeasts, and bacteria) in physiological buffer. By means of this procedure, cells can also be transferred from one glass slide to another one or onto an agar medium.

Isolation of Optically Targeted Single Bacteria by Application of Fluidic Force Microscopy to Aerobic Anoxygenic Phototrophs from the Phyllosphere

“…1a). It was previously shown that chosen microorganisms adsorbed on a glass surface in liquid can be attached to the cantilever aperture by application of underpressure, moved, and released onto another defined position on the same surface by application of a short overpressure pulse (36). Here we demonstrate that this protocol can be extended to isolate bacteria from environmental samples.…”

“…To explore and establish FluidFM for single-bacterium isolation, different parameters were tested and optimized to ensure efficient isolation of a wide range of randomly chosen bacteria from environmental samples. Cantilevers with an aperture diameter of 8 m were used; however, instead of cantilevers with a default channel height of 1 m, as used in previous studies (36,37,51), cantilevers with a channel height of only 0.5 m were used, because they ensured that the targeted bacteria remained confined at the aperture, where they could be easily spotted, and were not sucked into the channel of the probe. Plasma cleaning and coating the cantilever with PLL-g-PEG reduced the chance that a bacterium would irreversibly bind to the cantilever (38).…”

3D Nanofabrication of Fluidic Components by Corner Lithography

“…These modified pyramids can be applied as functional tips in Atomic Force Microscopy (AFM) based liquid deposition techniques, such as dip‐pen nanolithography (DPN),5 Nano‐Scale Dispensing (NADIS),6–8 and fountain pen based lithography 9, 10. An emerging application of fluidic AFM is in single cell biological or biophysical experiments 11. Pyramids containing nano‐apertures could find application as advanced electrospray emitters for the generation of nano‐scale droplets 12.…”

Cell Adhesion on Dynamic Supramolecular Surfaces Probed by Fluid Force Microscopy-Based Single-Cell Force Spectroscopy

“…3 Previously, single-cell force spectroscopy has been successfully performed by various groups using AFM cantilevers functionalized with cell-adhesive ligands. 29−31 Such cantilevers have been used to pick up individual cells and bring them in contact with a desired surface.…”