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2. THICK-ELECTRODE DEP FOR SINGLE-CELL 3D ROTATION
selected in the frame sequence, and the angle and rotation time corresponding to the rotation of
the feature point for about one revolution are tracked. e angular velocity can be calculated from
the angle/time.
2.6 SINGLECELL 3D ROTATION EXPERIMENT
2.6.1 CELL SAMPLE PREPARATION
Culture environment:
• cell culture incubator: ermo LS-C0150; 37 ° C, 5% CO2 concentration.
• PBS (Corning, U.S.);
• trypsin (Corning, U.S.);
• fetal bovine serum (Sijiqing, China);
• DMEM (ermo Fisher Scientic, U.S.);
• penicillin Streptomycin (Corning, U.S.); and
• cell culture medium: 90% DMEM medium, 9% fetal calf serum1%, double antibody.
Four types of cellsHeLa, B, HepaRG, C3H10were used in this experiment. B cells are
suspended cells, and the other three cells are adherent cells. For adherent cells, sample preparation
steps are following. First, the medium, PBS and trypsin are heated to 37° C, then the medium is
aspirated with a pipette. Subsequently, trypsin is added, after digesting for 10 minutes at 37°C,
the cells change the adherent state to suspended. And then the same dose of medium is added to
trypsin to stop the digestion process. Using pipette to transfer the suspended cells to a centrifuge
tube, centrifuge at 1,000 r/min for 5 min. After centrifugation, aspirate the supernatant and add
the medium to disperse the cells at the bottom of the centrifuge tube. DEP buer is then added
for use as an experimental sample.
Suspended cells are prepared by following the above steps for adherent cells, but after digestion.
2.6.2 CELL CAPTURE VALIDATION
e ow rate of cell solution (20 µm/s) was set in the experiment. At this ow rate, the cells are
easily tracked under a bright eld microscope. Under the action of laminar ow, the cells will move
forward along the streamline. When the cells are in the center of the microchannel, they will stop
at the V-shape structure. After one cell was captured, it was released from the trap site using a back
ow. e ow rate of 40 µm/s was used to produce a Stokes force of ~24 pN. When the single
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