Figure 1
From: Automated single cell isolation from suspension with computer vision
Automated micropipette for single cell isolation from a thin layer of suspension.
Panel (a) shows the concept of cell sorting. Cells are detected by computer vision using the objective lens of an inverted microscope. Cell suspension is confined into a thin ~100 μm layer of culture medium or buffer covered with oil to avoid the convection-driven floating of cells. The glass micropipette with an inner diameter of D = 30 μm approaches the surface of the dish to a distance of h = 5 μm. Targeted cell is picked up by a slight vacuum connected to the micropipette and controlled by a high speed fluid valve. Inhibitory effect of cell confinement into a thin layer on cell floating is shown in (b). Wells of the miniature plate (shown in (c–e)) printed into the Petri dish further decreased convection. Panel c presents the schematics of the experiment. Initial suspension was kept in a larger, 5 × 5 mm2 square. Green and red dots represent cells to be isolated and cells not needed, respectively. When using a sparse suspension (Fig. 2), selected single cells could be directly moved from this square to the other large square or into smaller, 2 × 2 mm2 squares in the same dish or into PCR tubes (not shown). Photos of the miniature multiwell plates printed into 35 mm plastic Petri dishes with a resolution of 0.2 mm using a commercial 3D printer (Ultimaker) are shown in panel (d–e). (d) side view of a 24-well plate with 2 × 2 mm2 wells beside the two larger (5 × 5 mm2) squares inside the Petri dish. Four 5 × 5 mm2 wells (shown in (e)) were used when isolating single cells from a dense culture in successive pickup and deposition steps. We printed the structures with a height of 0.5 or 1.0 mm.
