High speed ccd camera

The microfluidic system consists of ten microfluidic chips of micro-ellipse filters, plastic tubes, syringes and syringe pumps. A syringe pump was used to load cell suspension into the chip. The syringe attached to the pump was connected to inlet of the chip through plastic tubing as shown in Fig. 3. An inverted phase contrast fluorescence microscope (Nikon, Japan) equipped with a high speed CCD camera (Nikon, Japan) was used to observe.

The microfluidic system is composed of the triplet-microchannel spiral microfluidic chip (Spiral-Slits Chip), plastic tubing, syringes and syringe pumps^{17 (link)}. A syringe pump was used to load cell suspension into Spiral chip. The syringe attached to the pump was connected to the inlet of the triplet-microchannel spiral microfluidic chip through plastic tubing³⁰ . An inverted phase contrast fluorescence microscope (Nikon, Japan) equipped with a high-speed CCD camera (Nikon, Japan) was used to observe. This device was fabricated in Polydimethylsiloxane (PDMS) bonded to a glass substrate^{17 (link)}.

MCF-7 cells (human breast adenocarcinoma) and HepG2 cells (hepatocellular carcinoma) were provided by Tianjin Medical University Cancer Institute and Hospital. Hela cells were offered by Peking University Third Hospital. Cells were cultured in Dulbecco’s Modified Eagle Medium (DMEM) (HyClone, USA) medium supplemented with 10% fetal bovine serum (FBS) (GIBCO, USA) and 1% penicillin-streptomycin (Ying Reliable biotechnology, China) and incubated in a humidified atmosphere at 37 °C with 5% CO atmosphere. When cell lines were grown as adherent monolayers to 95% confluence, they were detached from the culture dishes with 0.25% Trypsin solution. The cell suspension was diluted to obtain a desired cell concentration using a hemocytometer. Cells were labeled by Calcein AM (BIOTIUM, USA) and Hoechst (Molecular Probes, Solarbio Corp., China). Observation of CTCs was used an inverted phase contrast fluorescence microscope (Nikon, Japan) equipped with a high speed CCD camera (Nikon, Japan) and counted by using hemocytometer to around 100 cells in 1 ml PBS containing 1% BSA and 0.05% tween-20.