A Sensitive Chemotaxis Assay Using a Novel Microfluidic Device
Figure 4
Microfluidic device assay. (a) Dose-response curves with and without prior MMC treatment. MMC-treated and nontreated SMC were placed in side cell wells, with different concentrations of PDGF (5 ng/mL, 10 ng/mL, 25 ng/mL, 50 ng/mL, and 100 ng/mL) present in the central source wells. Migration was measured after Hoechst 33342 staining and fluorescence microscopy after 48 h, using the Matlab program to calculate total migration. Controls (SMC medium only) and every concentration of PDGF were evaluated in triplicate devices. Significant differences can be seen from 5 ng/mL to 100 ng/mL PDGF compared with the control (). (b) Chemokinesis versus chemotaxis in microfluidic devices. MMC-treated SMC with or without 2.5 ng/mL PDGF were plated in the central cell well; 2.5 ng/mL or 50 ng/mL PDGF were added to the side source wells. With no PDGF present in the central cell well, the assay shows significantly greater total migration after 48 h with 50 ng/mL in the source well (“0–50”) versus 2.5 ng/mL in the source well (“0–2.5”). The presence of 2.5 ng/mL PDGF in the central cell well leads to significantly greater total migration when there is a concentration gradient (“2.5–50”; ) attributable to a local chemokinesis effect. In the absence of a gradient (“2.5–2.5”), there is a chemokinesis-associated migration which is significantly less than the migration seen when a gradient is present (“0–2.5”; ). (c) Time-course experiment performed as panel (b).
