Polycarbonate membrane inserts

A cell migration assay was examined by using a 24-well unit containing 8 μm (pore size) polycarbonate membrane inserts (BD Biosciences, San Jose, CA). Approximately 2.0 × 10⁴ cells were added to the upper chamber in medium, and 600 μl of culture media containing 20% fetal bovine serum was added to the bottom chamber. Cells were allowed to migrate at 37°C for 24-48 h toward the lower reservoir. Cells in the upper chambers were removed, and cells in the bottom chambers were fixed with paraformaldehyde and stained with crystal violet. The experiments were repeated three times with duplicate samples.

For the cell migration assay, a 24-well plate containing 8-μm (pore size) polycarbonate membrane inserts (BD Biosciences, San Jose, CA) was used. Approximately 4×10⁴ cells were added to the upper chamber of each well and allowed to migrate at 37°C for 24-36 hours toward the lower reservoir, which contained culture medium with 2.5% fetal bovine serum. Cell invasion was tested using the Transwell chamber invasion assay (Matrigel-coated membrane, BD Biosciences, Bedford, MA). 1.0×10⁴ cells were seeded in serum-free medium into the upper chamber and allowed to invade toward 15% fetal calf serum as a chemoattractant in the lower chamber. After 24-48 h (according to their respective invasive ability), cells that had invaded through the Matrigel matrix and adhered to the underside of the membrane were fixed in 4% paraformaldehyde for 15 minutes and stained with crystal violet for 30 minutes. All cells were counted at ×200 magnification under a microscope. The assay was repeated three times with duplicate samples, and five fields were counted for each sample.