Dynamic optical range for variable-scale analysis of cellular behavior.

<p>a) A panoramic micrograph was automatically stitched from multiple adjacent fields of view to visualize the microchannel array. (Pictured: HOS cells after 5 h of migration). b) A single field of view from the stitched montage shown in panel (a), captured with a 10× objective. (Pictured: cells migrating in 50 µm and 20 µm microchannels). c) A cropped section of the image in panel (b) shown at 100% zoom.</p

Confocal analysis of HOS cells migrating in 3 µm-wide microchannels.

<p>(a) A composite image (three-color fluorescence+differential interference contrast) depicts two cells inside 3 µm-wide microchannels, and a third cell entering a microchannel. (b) DAPI staining indicates an elongated nucleus distinct from the typical nuclear morphology on a flat 2D surface. (c) FITC-conjugated anti-α-tubulin labeling indicates that tubulin concentrates in a cytoplasmic and perinuclear region. (d) Phalloidin staining for F-actin revealed a specific enrichment of F-actin at the cell poles. (e) A fluorescence overlay image indicates the distinct subcellular localization of tubulin and F-actin, which is quantitatively represented in a color-coded intensity profile (sampled region is indicated by vertical yellow line) (f).</p

Design and characterization of the microfludic cell migration chamber.

<p>a) Schematic of cell migration chamber. The microfluidic device consists of an array of microchannels of varying width, ranging from 3 µm to 50 µm. b) A representative SEM image of vertical microchannels spaced 50 µm apart. c) Quantitative heatmap of fluorescence intensity indicates the stability of a chemokine-like gradient. The lower panel is a quantitative representation of fluorescence signal decay plotted as arbitrary intensity units as a function of distance from chemokine stream over the course of 9 h. The microchannel position is indicated by dotted green lines, which corresponds to a drop in fluorescence intensity due to occlusions of the FITC-dextran by the PDMS walls. d) Fluorescence intensity measurement over time at either sides of the microchannels, i.e., cell entrance (2) and cell exit (1) regions.</p

Direct comparison of multiple cell types in an enclosed migration system.

<p>(a) A representative image of mixture of MCF-7 and MDA-MB-2321 cells migrating through 20 µm and 10 µm wide microchannels. A surface map of fluorescence intensity (b) and horizontal intensity profile (c) are shown as adiditonal methods for quantifying the extent of migration for each cell type (horizontal axis of panel (c) drawn to scale to correspond with cell position in panel (a)).</p

The influence of channel width on migratory cell morphology and migration speed.

<p>HOS cells are pictured as they migrate ‘upward’ toward a chemokine source through microchannels of various widths. Cells migrating in 50 µm (a) and 20 µm (b) -wide channels exhibit morphologies similar to cells on a planar surface (f). Cells migrating through 10 µm (c) and 6 µm (d) channels are laterally restricted by the channel walls. Cells migrating through 3 µm-wide channels (e) undergo significant deformation, becoming uniform and morphologically de-polarized. Scale bar for (a–f) is indicated in panel (f) as 50 µm. g) Cell migration speed inside different channels of each dimension was calculated, and shown to be influenced by microchannel width (error bars depict standard error of the mean).</p